Metal plate, method of manufacturing metal plate, and method of manufacturing mask by using metal plate

ABSTRACT

A metal plate for manufacturing a deposition mask with reduced variation in dimension of through-holes. An average value of plate thicknesses of the metal plate in a longitudinal direction is within a ±3% range around a predetermined value. When an average value of the plate thicknesses of the metal plate in the longitudinal direction is represented as A, and a value obtained by multiplying a standard deviation of the plate thicknesses of the metal plate in the longitudinal direction by 3 is represented as B, (B/A)×100(%) is ≦5%. When a value obtained by multiplying a standard deviation of the plate thicknesses of the metal plate in the width direction by 3 is represented as C, and a value of a plate thickness of the metal plate at a central portion in the width direction is represented as X, (C/X)×100(%) is ≦3%.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a metal plate for use in manufacturinga deposition mask with a plurality of through-holes formed therein. Inaddition, the present invention relates to a method of manufacturing themetal plate. In addition, the present invention relates to a method ofmanufacturing a deposition mask with a plurality of through-holes formedtherein, by using the metal plate.

Background Art

A display device used in a portable device such as a smart phone and atablet PC is required to have high fineness, e.g., a pixel density of300 ppi or more. In addition, there is increasing demand that theportable device is applicable in the full high-definitions standard. Inthis case, the pixel density of the display device needs to be 450 ppior more, for example.

An organic EL display device draws attention because of its excellentresponsibility and low power consumption. A known method of formingpixels of an organic EL display device is a method which uses adeposition mask including through-holes that are arranged in a desiredpattern, and forms pixels in the desired pattern. To be specific, adeposition mask is firstly brought into tight contact with a substratefor organic EL display device, and then the substrate and the depositionmask in tight contact therewith are put into a deposition apparatus soas to deposit an organic material and so on. In general, a depositionmask can be manufactured by forming through-holes in a metal plate bymeans of an etching process using photolithographic technique (forexample, Patent Document 1). For example, a resist film is firstlyformed on the metal plate. Then, the resist film, with which an exposuremask is in tight contact, is exposed to form a resist pattern.Thereafter, through-holes are formed by etching areas of the metalplate, which are not covered with the resist pattern.

Patent Document 1: JP2004-039319A

DISCLOSURE OF THE INVENTION

When a layer of a deposition material is formed on a substrate with theuse of a deposition mask, the deposition material adheres not only tothe substrate but also to the deposition mask. For example, some of thedeposition material moves toward the substrate along a direction largelyinclined with respect to a normal direction of the deposition mask. Sucha deposition material reaches a wall surface of a through-hole of thedeposition mask and adheres thereto, before it reaches the substrate. Inthis case, the deposition material is not likely to adhere to an area ofthe substrate, which is located near the wall surface of thethrough-hole of the deposition mask, so that a thickness of thedeposition material adhered to this area may be smaller than a thicknessof another portion and/or there may be a portion to which no depositionmaterial adheres. Namely, the deposition near the wall surface of thethrough-hole of the deposition mask may become unstable. Thus, when thisdeposition mask is used for forming pixels of an organic EL displaydevice, dimensional precision of each pixel and positional precisionthereof lower, which lowers luminous efficiency of the organic ELdisplay device.

One of possible solutions to this problem is to reduce a thickness of ametal plate used for manufacturing a deposition mask. This is because,since the thickness of the metal plate is reduced, a height of a wallsurface of a through-hole of a deposition mask can be reduced, whereby arate of a deposition material, which adheres to the wall surface of thethrough-hole, can be lowered. In order to obtain a metal plate with areduced thickness, it is necessary to increase a reduction ratio uponmanufacture of the metal plate by rolling a base metal. However, thelarger the reduction ratio is, the larger the non-uniformity degree ofdeformation caused by the rolling process becomes. For example, it isknown that, if an elongation percentage of a metal plate differsdepending on a position in a width direction (direction perpendicular toa transport direction of the base metal), the metal plate has acorrugation (corrugated shape). Thus, there are limitations in reducingthe thickness of the metal plate. As a result, in order to reduce theheight of the wall surface in the through-hole of the deposition mask,not only the method of reducing the thickness of the metal plate butalso another method is required to be employed.

As described above, the through-holes in the deposition mask are formedby etching. Thus, the height of the wall surface of the through-hole inthe deposition mask can be precisely controlled, by adjusting etchingconditions such as an etching period of time, an etchant type and so on.Namely, the height of the wall surface of the through-hole in thedeposition mask can be sufficiently reduced by dissolving the metalplate by etching in a thickness direction thereof, in addition to thereduction in thickness of the metal plate. When a metal plate is etchedby injecting an etchant to the metal plate at a predetermined pressure,the injection pressure is one of the etching conditions.

On the other hand, a plate thickness of the metal plate is not uniform,and the plate thickness more or less varies. Thus, when a metal plate isetched under the same etching conditions, a shape of a through-hole tobe formed varies depending on the plate thickness of the metal plate.When the shape of the through-hole varies depending on a position, adimension of the deposition material adhering to the substrate alsovaries depending on a location.

The present invention has been made in view of the above problems. Theobject of the present invention is to provide a metal plate that can beused for manufacturing a deposition mask with through-holes formedtherein with a high degree of dimensional precision. In addition, theobject of the present invention is to provide a method of manufacturingthe metal plate and a method of manufacturing the mask.

SUMMARY OF THE INVENTION

The present invention is [claim 1]: a method of manufacturing anelongated metal plate used for manufacturing a deposition mask having aplurality of through-holes formed therein, the method comprising:

a rolling step in which a base metal is rolled so as to obtain the metalplate having an average value of plate thicknesses in a longitudinaldirection is within a ±3% range around a predetermined value; and

a cutting step in which one end and the other end of the metal plate ina width direction are cut off over a predetermined range;

wherein the following two conditions (1) and (2) are satisfied as to avariation in plate thickness of the metal plate:

(1) when an average value of the plate thicknesses of the metal plate inthe longitudinal direction is represented as A, and a value obtained bymultiplying a standard deviation of the plate thicknesses of the metalplate in the longitudinal direction by 3 is represented as B,(B/A)×100(%) is 5% or less; and(2) when a value obtained by multiplying a standard deviation of theplate thicknesses of the metal plate in the width direction isrepresented as C, and a value of a plate thickness of the metal plate ata central portion in the width direction, which is obtained when platethicknesses of the metal plate are measured along the width direction inorder to calculate the standard deviation of the plate thicknesses ofthe metal plate in the width direction, is represented as X,(C/X)×100(%) is 3% or less.

The through-holes in the deposition mask manufactured of the metal platemay be formed by etching the elongated metal plate which is beingtransported.

The present invention is [claim 2]: a method of manufacturing anelongated metal plate used for manufacturing a deposition mask having aplurality of through-holes formed therein, the method comprising:

a film manufacturing step in which the metal plate is obtained by aplating process, wherein an average value of plate thicknesses of themetal plate in a longitudinal direction is within a ±3% range around apredetermined value; and

a cutting step in which one end and the other end of the metal plate ina width direction are cut off over a predetermined range;

wherein the following two conditions (1) and (2) are satisfied as to avariation in plate thickness of the metal plate:

(1) when an average value of the plate thicknesses of the metal plate inthe longitudinal direction is represented as A, and a value obtained bymultiplying a standard deviation of the plate thicknesses of the metalplate in the longitudinal direction by 3 is represented as B,(B/A)×100(%) is 5% or less; and(2) when a value obtained by multiplying a standard deviation of theplate thicknesses of the metal plate in the width direction isrepresented as C, and a value of a plate thickness of the metal plate ata central portion in the width direction, which is obtained when platethicknesses of the metal plate are measured along the width direction inorder to calculate the standard deviation of the plate thicknesses ofthe metal plate in the width direction, is represented as X,(C/X)×100(%) is 3% or less.

The through-holes in the deposition mask manufactured of the metal platemay be formed by etching the elongated metal plate which is beingtransported.

In the method of manufacturing a metal plate according to the presentinvention, [claim 3]: the plate thickness of the metal plate ispreferably 80 μm or less.

In the method of manufacturing a metal plate according to the presentinvention, [claim 4]: the standard deviation of the plate thicknesses inthe width direction of the metal plate may be calculated based on theplate thicknesses of the metal plate, the plate thicknesses beingmeasured at intersections between imaginary lines the number of which ism (m is a natural number of 2 or more), each extending on the metalplate in the longitudinal direction, and an imaginary line(s) the numberof which is n (n is a natural number of 1 or more), each extending onthe elongated metal plate in the width direction. In this case, m>n.

In the method of manufacturing a metal plate according to the presentinvention, [claim 5]: the base metal may be made of an iron alloycontaining nickel.

The present invention is [claim 6]: an elongated metal plate used formanufacturing a deposition mask having a plurality of through-holesformed therein,

wherein:

an average value of plate thicknesses in a longitudinal direction of themetal plate is within a ±3% range around a predetermined value; and

the following two conditions (1) and (2) are satisfied as to a variationin plate thickness of the metal plate:

(1) when an average value of the plate thicknesses of the metal plate inthe longitudinal direction is represented as A, and a value obtained bymultiplying a standard deviation of the plate thicknesses of the metalplate in the longitudinal direction by 3 is represented as B,(B/A)×100(%) is 5% or less; and(2) when a value obtained by multiplying a standard deviation of theplate thicknesses of the metal plate in the width direction isrepresented as C, and a value of the plate thickness of the metal platein a central portion in the width direction, which is obtained when theplate thickness of the metal plate is measured along the width directionin order to calculate the standard deviation of the plate thicknesses ofthe metal plates in the width direction is represented as C,(C/X)×100(%) is 3% or less.

In the metal plate according to the present invention, [claim 7]: theplate thickness of the metal plate is preferably 80 μm or less.

In the metal plate according to the present invention, [claim 8]: thestandard deviation of the plate thicknesses in the width direction ofthe metal plate may be calculated based on the plate thicknesses of themetal plate, the plate thicknesses being measured at intersectionsbetween imaginary lines the number of which is m (m is a natural numberof 2 or more), each extending on the metal plate in the longitudinaldirection, and an imaginary line(s) the number of which is n (n is anatural number of 1 or more), each extending on the elongated metalplate in the width direction. In this case, m>n.

In the metal plate according to the present invention, [claim 9]: thebase metal may be made of an iron alloy containing nickel.

The present invention is [claim 10]: a method of manufacturing adeposition mask having a plurality of through-holes formed therein, themethod comprising:

a step of preparing an elongated metal plate having an average value ofplate thicknesses in a longitudinal direction is within a ±3% rangearound a predetermined value;

a resist-pattern forming step in which a resist pattern is formed on themetal plate; and

an etching step in which an area of the metal plate, which is notcovered with the resist pattern, is etched to form a recess whichbecomes a through-hole in the metal plate;

wherein the following two conditions (1) and (2) are satisfied as to avariation in plate thickness of the metal plate:

(1) when an average value of the plate thicknesses of the metal plate inthe longitudinal direction is represented as A, and a value obtained bymultiplying a standard deviation of the plate thicknesses of the metalplate in the longitudinal direction by 3 is represented as B,(B/A)×100(%) is 5% or less; and(2) when a value obtained by multiplying a standard deviation of theplate thicknesses of the metal plate in the width direction isrepresented as C, and a value of a plate thickness of the metal plate ata central portion in the width direction, which is obtained when platethicknesses of the metal plate are measured along the width direction inorder to calculate the standard deviation of the plate thicknesses ofthe metal plate in the width direction, is represented as X,(C/X)×100(%) is 3% or less.

In the method of manufacturing a deposition mask according to thepresent invention, [claim 11]: the plate thickness of the metal plate ispreferably 80 μm or less.

In the method of manufacturing a deposition mask according to thepresent invention, [claim 12]: the standard deviation of the platethicknesses in the width direction of the metal plate may be calculatedbased on the plate thicknesses of the metal plate, the plate thicknessesbeing measured at intersections between imaginary lines the number ofwhich is m (m is a natural number of 2 or more), each extending on themetal plate in the longitudinal direction, and an imaginary line(s) thenumber of which is n (n is a natural number of 1 or more), eachextending on the elongated metal plate in the width direction. In thiscase, m>n.

In the method of manufacturing a deposition mask according to thepresent invention, [claim 13]: the base metal may be made of an ironalloy containing nickel.

In the method of manufacturing a deposition mask according to thepresent invention, [claim 14]:

the deposition mask may have a first surface and a second surface, thefirst surface facing a deposition material and the second surface facinga substrate when the deposition material is deposited onto the substrateusing the deposition mask;

the resist pattern formed by the resist-pattern forming step may includea first resist pattern formed on a first surface of the metal plate,which corresponds to the first surface of the deposition mask, and asecond resist pattern formed on a second surface of the metal plate,which corresponds to the second surface of the deposition mask;

the recess formed by the etching step may include a plurality of firstrecesses formed by etching an area of the first surface of the metalplate, which is not covered with the first resist pattern, and aplurality of second recesses formed by etching an area of the secondsurface of the metal plate, which is not covered with the second resistpattern; and

the etching step may be performed such that the first recess and thesecond recess corresponding to the first recess are connected to eachother.

In this case, a distance from the second surface of the deposition maskto a connection portion where the first recess and the second recess areconnected, in a direction along a normal direction of the metal plate ispreferably 6 μm or less.

In the method of manufacturing a deposition mask according to thepresent invention, [claim 15]: the deposition mask may be divided intoan effective area in which the plurality of through-holes is formed, anda peripheral area located around the effective area; and

the etching step may be performed such that the first surface of themetal plate is etched over all the effective area.

In the method of manufacturing a deposition mask according to thepresent invention, [claim 16]: the deposition mask may be divided intoan effective area in which the plurality of through-holes is formed, anda peripheral area located around the effective area; and

the etching step may be performed such that the first surface of themetal plate is not etched over all the effective area, so that a portionthat is not etched remains as a top portion.

According to the present invention, it is possible to obtain adeposition mask in which a variation in dimension of through-holesdimension is restrained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view for explaining an embodiment of the present invention,which is a schematic plan view showing an example of a deposition maskapparatus including a deposition mask.

FIG. 2 is a view for explaining a deposition method by using thedeposition mask apparatus shown in FIG. 1.

FIG. 3 is a partial plan view showing the deposition mask shown in FIG.1.

FIG. 4 is a sectional view along the IV-IV line of FIG. 3.

FIG. 5 is a sectional view along the V-V line of FIG. 3.

FIG. 6 is a sectional view showing VI-VI line of FIG. 3.

FIG. 7 is an enlarged sectional view showing the through-hole shown inFIG. 4 and an area near the through-hole.

FIG. 8A is a sectional view showing an example of a through-hole that isformed when a plate thickness of a metal plate is smaller than a targetspecification value.

FIG. 8B is a sectional view showing an example of a through-hole that isformed when a plate thickness of a metal plate is larger than a targetspecification value.

FIG. 9(a) is a view showing a step in which a metal plate having adesigned thickness is obtained by rolling a base metal.

FIG. 9(b) is a view showing a step in which the metal plate obtained byrolling is annealed.

FIG. 10 is a view showing that a plurality of deposition masks isassigned to an elongated metal plate.

FIG. 11A is a sectional view showing an example in which a platethickness of a metal plate varies in a rolling direction (longitudinaldirection).

FIG. 11B is a sectional view showing an example in which a platethickness of a metal plate varies in a width direction.

FIG. 12 is a schematic view for generally explaining an example of amethod of manufacturing the deposition mask shown in FIG. 1.

FIG. 13 is a view for explaining an example of the method ofmanufacturing the deposition mask, which is a sectional view showing astep in which a resist film is formed on a metal plate.

FIG. 14 is a view for explaining an example of the method ofmanufacturing the deposition mask, which is a sectional view showing astep in which an exposure mask is brought into tight contact with theresist film.

FIG. 15 is a view for explaining an example of the method ofmanufacturing the deposition mask, showing an elongated metal plate in asection along a normal direction.

FIG. 16 is a view for explaining an example of the method ofmanufacturing the deposition mask, showing the elongated metal plate ina section along the normal direction.

FIG. 17 is a view for explaining an example of the method ofmanufacturing the deposition mask, showing the elongated metal plate ina section along the normal direction.

FIG. 18 is a view for explaining an example of the method ofmanufacturing the deposition mask, showing the elongated metal plate ina section along the normal direction.

FIG. 19 is a view for explaining an example of the method ofmanufacturing the deposition mask, showing the elongated metal plate ina section along the normal direction.

FIG. 20 is a view for explaining an example of the method ofmanufacturing the deposition mask, showing the elongated metal plate ina section along the normal direction.

FIG. 21 is a view for explaining an example of the method ofmanufacturing the deposition mask, showing the elongated metal plate ina section along the normal direction.

FIG. 22 is a view showing a modification example of the deposition maskapparatus including a deposition mask.

FIG. 23 is a view showing measurement points at which dimensions ofthrough-holes formed in the deposition mask are measured.

FIGS. 24(a) to 24(c) are views showing calculation results of avariation in plate thickness in the longitudinal direction of elongatedmetal plates of 11^(th) to 17^(th) winding bodies, 21^(st) to 27^(th)winding bodies, and 31^(st) to 37^(th) winding bodies.

FIGS. 25(a) to 25(c) are views showing calculation results of avariation in dimension of through-holes in deposition masks manufacturedfrom the elongated metal plates of the 11^(th) to 17^(th) windingbodies, the 21^(st) to the 27^(th) winding bodies, and the 31^(st) tothe 37^(th) winding bodies.

FIGS. 26(a) to 26(c) are views showing calculation results of an averagevalue of plate thicknesses and a variation in plate thickness in thelongitudinal direction of elongated metal plates of 41^(st) to 47^(th)winding bodies, 51^(st) to 57^(th) winding bodies, and 61^(st) to67^(th) winding bodies.

FIGS. 27(a) to 27(c) are views showing calculation results of avariation in dimension of through-holes and a maximum dimension of a topportion of deposition masks manufactured from the elongated metal platesof the 41^(st) to the 47^(th) winding bodies, the 51^(st) to the 57^(th)winding bodies, and the 61^(st) to the 67^(th) winding bodies.

FIG. 28 is a view showing measurement points at which plate thicknessesof an elongated metal plate are measured.

FIG. 29(a) to (c) are views showing calculation results of a variationin plate thickness in the width direction of elongated metal plates of71^(st) to 77^(th) winding bodies, 81^(st) to 87^(th) winding bodies,and 91^(st) to 97^(th) winding bodies.

FIGS. 30(a) to 30(c) are views showing calculation results of avariation in dimension of through-holes in deposition masks manufacturedfrom the elongated metal plates of the 71^(st) to the 77^(th) windingbodies, the 81^(st) to the 87^(th) winding bodies, and the 91^(st) tothe 97^(th) winding bodies.

FIGS. 31(a) to 31(c) are views showing calculation results of avariation in plate thickness in the longitudinal direction of elongatedmetal plates of 101^(st) to 107^(th) winding bodies, 111^(th) to117^(th) winding bodies and 121^(st) to 127^(th) winding bodies.

FIGS. 32(a) to 32(c) are views showing calculation results of avariation in dimension of through-holes in deposition masks manufacturedfrom the elongated metal plates of the 101^(st) to the 107^(th) windingbodies, the 111^(th) to the 117^(th) winding bodies, and the 121^(st) tothe 127^(th) winding bodies.

FIGS. 33(a) to 33(c) are views showing calculation results of an averagevalue of plate thicknesses and a variation in plate thickness in thelongitudinal direction of elongated metal plates of 131^(st) to 137^(th)winding bodies, 141^(st) to 147^(th) winding bodies, and 151^(st) to157^(th) winding bodies.

FIGS. 34(a) to 34(c) are views showing calculation results of avariation in dimension of through-holes and a maximum dimension of a topportion of deposition masks manufactured from the elongated metal platesof the 131^(st) to the 137^(th) winding bodies, the 141^(st) to the147^(th) winding bodies, and the 151^(st) to the 157^(th) windingbodies.

FIGS. 35(a) to 35(c) are views showing calculation results of adeviation in plate thickness in the width direction of elongated metalplates of 161^(st) to 167^(th) winding bodies, 171^(st) to 177^(th)winding bodies, and 181^(st) to 187^(th) winding bodies.

FIGS. 36(a) to 36(c) are views showing calculation results of avariation in dimension of through-holes in deposition masks manufacturedfrom the elongated metal plates of the 161^(st) to the 167^(th) windingbodies, the 171^(st) to the 177^(th) winding bodies, and the 181^(st) tothe 187^(th) winding bodies.

FIG. 37 is a view showing a film forming apparatus for manufacturing ametal plate by a plating process.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention will be described herebelow withreference to the drawings. In the drawings attached to thespecification, a scale dimension, an aspect ratio and so on are changedand exaggerated from the actual ones, for the convenience of easiness inillustration and understanding.

FIGS. 1 to 21 are views for explaining an embodiment of the presentinvention. In the below embodiment and its modification examples, amethod of manufacturing a deposition mask, which is used for patterningan organic material in a desired pattern on a substrate when an organicEL display device is manufactured, is described by way of example.However, not limited to this application, the present invention can beapplied to a method of manufacturing a deposition mask to be used invarious applications.

In this specification, the terms “plate”, “sheet” and “film” are notdifferentiated from one another based only on the difference of terms.For example, the “plate” is a concept including a member that can bereferred to as sheet or film. Thus, for example, “metal plate” is notdifferentiated from a member that is referred to as “metal sheet” or“metal film” based only on the difference of terms.

In addition, the term “plate plane (sheet plane, film plane)” means aplane corresponding to a plane direction of a plate-like (sheet-like,film-like) member as a target, when the plate-like (sheet-like,film-like) member as a target is seen as a whole in general. A normaldirection used to the plate-like (sheet-like, film-like) member means anormal direction with respect to a plate plane (sheet surface, filmsurface) of the member.

Further, in this specification, terms specifying shapes, geometricconditions and their degrees, e.g., “parallel”, “perpendicular”, “same”,“similar” etc., are not limited to their strict definitions, butconstrued to include a range capable of exerting a similar function.

(Deposition Mask Apparatus)

Firstly, an example of a deposition mask apparatus including depositionmasks to be manufactured is described with reference mainly to FIGS. 1to 6. FIG. 1 a plan view showing an example of the deposition maskapparatus including the deposition masks. FIG. 2 is a view forexplaining a method of using the deposition mask apparatus shown inFIG. 1. FIG. 3 is a plan view showing the deposition mask seen from afirst surface side. FIGS. 4 to 6 are sectional views seen fromrespective positions of FIG. 3.

The deposition mask apparatus 10 shown in FIGS. 1 and 2 includes aplurality of deposition masks 20 each of which is formed of a metalplate 21 of substantially a rectangular shape, and a frame 15 attachedto peripheries of the deposition masks 20. Each deposition mask 20 has anumber of through-holes 25 formed by etching the metal plate 21, whichhas a first surface 21 a and a second surface 21 b opposed to eachother, at least from the first surface 21 a. As shown in FIG. 2, thedeposition mask apparatus 10 is used for depositing a depositionmaterial to a substrate. The deposition mask apparatus 10 is supportedin a deposition apparatus 90 such that the deposition mask 20 faces alower surface of the substrate such as a glass substrate 92, onto whichthe deposition material is to be deposited.

In the deposition apparatus 90, the deposition mask 20 and the glasssubstrate 92 are brought into tight contact with each other by amagnetic force of magnets, not shown. In the deposition apparatus 90,there are disposed below the deposition mask apparatus 10 a crucible 94storing a deposition material (e.g., organic luminescent material) 98and a heater 96 for heating the crucible 94. The deposition material 98in the crucible 94 is evaporated or sublimated by heat applied from theheater 96 so as to adhere to the surface of the glass substrate 92. Asdescribed above, since the deposition mask 20 has a lot of through-holes25, the deposition material 98 adheres to the glass substrate 92 throughthe through-holes 25. As a result, a film of the deposition material 98is formed on the surface of the glass substrate 92 in a desired patterncorresponding to the positions of the through-holes 25 of the depositionmask 20.

As described above, in this embodiment, the through-holes 25 arearranged in each effective area 22 in a predetermined pattern. When acolor display is desired, an organic luminescent material for red color,an organic luminescent material for green color and an organicluminescent material for blue color may be sequentially deposited, whilethe deposition mask 20 (deposition mask apparatus 10) and the glasssubstrate 92 are relatively moved little by little along the arrangementdirection of the through-holes 25 (aforementioned one direction).

The frame 15 of the deposition mask apparatus 10 is attached to theperipheries of the rectangular deposition masks 20. The frame 15 isconfigured to hold each deposition mask in a taut state in order toprevent the deposition mask 20 from warping. The deposition masks 20 andthe frame 15 are fixed with respect to each other by spot welding, forexample.

The deposition process is performed inside the deposition apparatus 90in a high-temperature atmosphere. Thus, during the deposition process,the deposition masks 20, the frame 15 and the substrate 92, which areheld inside the deposition apparatus 90, are also heated. At this time,each of deposition masks 20, the frame 15 and the substrate 92 developdimensional change behaviors based on their respective thermal expansioncoefficients. In this case, when the thermal expansion coefficients ofthe deposition mask 20, the frame 15 and the substrate 92 largely differfrom one another, positioning displacement occurs because of thedifference in dimensional change. As a result, the dimensional precisionand the positional precision of the deposition material to be adhered tothe substrate 92 lower. In order to avoid this problem, the thermalexpansion coefficient of the deposition mask 20 and the frame 15 ispreferably equivalent to the thermal expansion coefficient of thesubstrate 92. For example, when a glass substrate 92 is used as thesubstrate 92, it is possible to use an iron alloy containing nickel. Tobe specific, an iron alloy such as an invar material containing 34-38%by weight of nickel, or a super invar material containing cobalt inaddition to nickel can be used. In this specification, a numerical rangeexpressed by the symbol “-” includes numerical values sandwiching thesymbol “-”. For example, a numerical range defined by the expression“34-38% by weight” is identical to a numerical range defined by anexpression “not less than 34% by weight and not more than 38% byweight”.

(Deposition Mask)

Next, the deposition mask 20 is described in detail. As shown in FIG. 1,in this embodiment, each deposition mask 20 is formed of the metal plate21, and has an outline of a substantially quadrangular shape in planview, more precisely, a substantially rectangular shape in plan view.The metal plate 21 of the deposition mask 20 includes the effective area22 in which the through-holes 25 are formed in a regular arrangement,and a peripheral area 23 surrounding the effective area 22. Theperipheral area 23 is an area for supporting the effective area 22, andis not an area through which the deposition material intended to bedeposited on the substrate passes. For example, in the deposition mask20 for use in depositing an organic luminescent material for organic ELdisplay device, the effective area 22 is an area in the deposition mask20, which faces a section on the substrate (glass substrate 92) to whichthe organic luminescent material is deposited to form pixels, i.e., asection on the substrate which provides a display surface of themanufactured substrate for organic EL display device. However, forvarious reasons, the peripheral area 23 may have a through-hole and/or arecess. In the example shown in FIG. 1, each effective area 22 has anoutline of a substantially quadrangular shape in plan view, moreprecisely, a substantially rectangular shape in plan view.

In the illustrated example, the effective areas 22 of the depositionmask 20 are aligned, at predetermined intervals therebetween, along onedirection in parallel with a longitudinal direction of the depositionmask 20. In the illustrated example, one effective area 22 correspondsto one organic EL display device. Namely, the deposition mask apparatus10 (deposition masks 20) shown in FIG. 1 enables a multifaceteddeposition.

As shown in FIG. 3, in the illustrate example, a plurality of thethrough-holes 25 formed in each effective area 22 are arranged atpredetermined pitches along two directions perpendicular to each other.An example of the through-hole 25 formed in the metal plate 21 isdescribed in more detail with reference mainly to FIGS. 3 to 6.

As shown in FIGS. 4 to 6, a plurality of the through-holes 25 extendbetween the first surface 20 a, which is one side along a normaldirection of the deposition mask 20, and the second surface 20 b, whichis the other side along the normal direction of the deposition mask 20,to pass through the deposition mask 20. In the illustrated example, asdescribed in more detail later, a first recess 30 is formed in the metalplate 21 by an etching process from the side of the first surface 21 aof the metal plate 21, which is the one side in the normal direction ofthe deposition mask, and a second recess 35 is formed in the metal plate21 from the side of the second surface 21 b, which is the other side inthe normal direction of the metal plate 21. The through-hole 25 iscomposed of the first recess 30 and the second recess 35.

As shown in FIGS. 3 to 6, a cross-sectional area of each first recess30, in a cross section along a plate plane of the deposition mask 20 ateach position along the normal direction of the deposition mask 20,gradually decreases from the side of the first surface 20 a of thedeposition mask 20 toward the side of the second surface 20 b. As shownin FIG. 3, a wall surface 31 of the first recess 30 extends in its allarea in a direction intersecting with the normal direction of thedeposition mask 20, and is exposed to the one side along the normaldirection of the deposition mask 20. Similarly, a cross-sectional areaof each second recess 35, in a cross section along the plate plane ofthe deposition mask 20 at each position along the normal direction ofthe deposition mask 20, may gradually decrease from the side of thesecond surface 20 b of the deposition mask 20 toward the side of thefirst surface 20 a. A wall surface 36 of the second recess 35 extends inits all area in a direction intersecting with the normal direction ofthe deposition mask 20, and is exposed to the other side along thenormal direction of the deposition mask 20.

As shown in FIGS. 4 to 6, the wall surface 31 of the first recess 30 andthe wall surface 36 of the second recess 35 are connected via acircumferential connection portion 41. The connection portion 41 isdefined by a ridge line of a bulging part where the wall surface 31 ofthe first recess 30, which inclined with respect to the normal directionof the deposition mask 20, and the wall surface 36 of the second recess35, which is inclined with respect to the normal direction of thedeposition mask 20, are merged with each other. The connection portiondefines a through-portion 42 where an area of the through-hole 25 isminimum in plan view of the deposition mask 20.

As shown in FIGS. 4 to 6, the adjacent two through-holes 25 in the otherside surface along the normal direction of the deposition mask, i.e., inthe second surface 20 b of the deposition mask 20, are spaced from eachother along the plate plane of the deposition mask. Namely, as in thebelow-described manufacturing method, when the second recesses 35 aremade by etching the metal plate 21 from the side of the second surface21 b of the metal plate 21, which will correspond to the second surface20 b of the deposition mask 20, the second surface 21 b of the metalplate 21 remains between the adjacent two recesses 35.

On the other hand, as shown in FIGS. 4 to 6, the adjacent two firstrecesses 30 are connected to each other on the one side along the normaldirection of the deposition mask, i.e., on the side of the first surface20 a of the deposition mask 20. Namely, as in the below-describedmanufacturing method, when the first recesses 30 are made by etching themetal plate 21 from the side of the first surface 21 a of the metalplate 21, which will correspond to the first surface 20 a of thedeposition mask 20, no first surface 21 a of the metal plate 21 remainsbetween the adjacent two first recesses 30. Namely, the first surface 21a of the metal plate 21 is etched as a whole over the effective area 22.According to the first surface 20 a of the deposition mask 20 formed bythese first recesses 30, when the deposition mask 20 is used such thatthe first surface 20 a of the deposition mask 20 faces the depositionmaterial 98 as shown in FIG. 2, a utilization efficiency of thedeposition material 98 can be effectively improved.

As described later, depending on an etching period of time, the etchingstep terminates, with the first surface 21 a of the metal plate 21partially remaining. In this case, a part of the first surface 21 a ofthe metal plate 21, which was not etched, remains as a top portiondescribed below. Also in this case, by suitably controlling a width ofthe top portion, the deposition material 98 can be utilized efficiently,and occurrence of shadow can be restrained.

As shown in FIG. 2, the deposition mask apparatus 10 is received in thedeposition apparatus 90. In this case, as shown by the two-dot chainlines in FIG. 4, the first surface 20 a of the deposition mask 20 islocated on the side of the crucible 94 holding the deposition material98, and the second surface 20 b of the deposition mask 20 faces theglass substrate 92. Thus, the deposition material 98 adheres to theglass substrate 92 through the first recess 30 whose cross-sectionalarea gradually decreases. As shown by the arrow in FIG. 4 the depositionmaterial 98 not only moves from the crucible 94 toward the glasssubstrate 92 along the normal direction of the glass substrate 92, butalso sometimes moves along a direction largely inclined with respect tothe normal direction of the glass substrate 92. At this time, when thethickness of the deposition mask 20 is large, most of the diagonallymoving deposition material 98 reaches the wall surface 31 of the firstrecess 30, before the deposition material 98 passes through thethrough-hole 25 to reach the glass substrate 92. In this case, the areaof the glass substrate 92 facing the through-hole 25 has an area wherethe deposition material 98 is likely to reach, and an area where thedeposition material 98 is unlikely to reach. Thus, in order that theutilization efficiency (a film-deposition efficiency: a rate of thedeposition material adhering to the glass substrate 92) of thedeposition material can be enhanced to save the expensive depositionmaterial, and that a film of the expensive deposition material can bestably and uniformly formed in the desired area, it is important toconstitute the deposition mask 20 such that the diagonally movingdeposition material 98 is made to reach the glass substrate 92 as muchas possible. Namely, it is advantageous to sufficiently increase aminimum angle θ1 (see FIG. 4) that is formed by a line L1, which passes,in the cross sections of FIGS. 4 to 6 perpendicular to the sheet planeof the deposition mask 20, the connection portion 41 having the minimumcross-sectional area of the through-hole 25 and another given positionof the wall surface 31 of the first recess 30, with respect to thenormal direction of the deposition mask 20.

One of possible methods of increasing the angle θ1 is that the thicknessof the deposition mask 20 is reduced so that the height of the wallsurface 31 of the first recess 30 and the height of the wall surface 36of the second recess 35 are reduced. Namely, it can be said that themetal plate 21, which has a thickness as small as possible as long asthe strength of the deposition mask 20 is ensured, is preferably used asthe metal plate 21 constituting the deposition mask 20.

As another possible method of increasing the angle θ1 is that theoutline of the first recess 30 is made optimum. For example, accordingto this embodiment, since the wall surfaces 31 of the adjacent two firstrecesses 30 are merged with each other, the angle θ1 is allowed to besignificantly large (see FIG. 4), as compared with a recess that doesnot merge with another recess, whose wall surfaces (outlines) are shownby the dotted lines. A reason therefor is described below.

As described in detail later, the first recess 30 is formed by etchingthe first surface 21 a of the metal plate 21. In general, a wall surfaceof the recess formed by etching has a curved shape projecting toward theerosion direction. Thus, the wall surface 31 of the recess formed byetching is steep in. an area where the etching starts, and is relativelylargely inclined in an area opposed to the area where the etchingstarts, i.e., the at the deepest point of the recess. On the other hand,in the illustrated deposition mask 20, since the wall surfaces 31 of theadjacent two first recesses 30 merge on the side where the etchingstarts, an outline of a portion 43 where distal edges 32 of the wallsurfaces 31 of the two first recesses 30 are merged with each other hasa chamfered shape instead of a steep shape. Thus, the wall surface 31 ofthe first recess 30 forming a large part of the through-hole 25 can beeffectively inclined with respect to the normal direction of thedeposition mask. That is to say, the angle θ1 can be made large. Thus,the deposition in a desired pattern can be precisely and stablyperformed, while the utilization efficiency of the deposition material98 can be effectively improved.

According to the deposition mask 20 in the present invention, theinclination angle θ1 formed by the wall surface 31 of the first recess30 with respect to the normal direction of the deposition mask can beeffectively increased, in the whole effective area 22. Thus, thedeposition in a desired pattern can be precisely and stably performed,while the utilization efficiency of the deposition material 98 can beeffectively improved.

Although not limited, the deposition mask 20 in this embodiment isparticularly effective when an organic EL display device having a pixeldensity of 450 ppi or more. Herebelow, an example of dimensions of thedeposition mask 20 required for manufacturing an organic EL displaydevice having such a high pixel density is described, with reference toFIG. 7. FIG. 7 is an enlarged sectional view showing the through-hole 25shown in FIG. 4 and an area near the through-hole.

In FIG. 7, a thickness of the deposition mask 20 is represented by asymbol t. The thickness t is a thickness of the deposition mask 20, witha part etched by the adjacent two first recesses 30 merging with eachother being neglected. Thus, it can be said that the thickness t is athickness of the metal plate 21. In addition, in FIG. 7, as one ofparameters related to the shape of the through-hole 25, a distance fromthe second surface 20 b of the deposition mask 20 up to the connectionportion 41 in a direction along the normal direction of the depositionmask 20 is represented by a symbol r₁. Further, a dimension of thesecond recess 35 on the second surface 20 b of the deposition mask 20 isrepresented by a symbol r₂. The dimension r2 is a size of the secondrecess 35 in a direction along the longitudinal direction of thedeposition mask 20. When an organic EL display device having a pixeldensity of 450 ppi or more is manufactured, the dimension r₂ of thesecond recess is set between 20-60 μm, for example. In this embodiment,in order for coping with an organic EL display device having a highpixel density, the dimension r₂ of the second recess 35 is set smallerthan that of a conventional deposition mask.

As described above, in order that a rate of the deposition materialadhering to the wall surface of the through-hole so as to improve thedeposition precision, it is effective to reduce the thickness t of thedeposition mask. In consideration of this point, in this embodiment, thethickness of the deposition mask (i.e., the plate thickness of the metalplate 21) t is preferably set to be 80 μm or less, for example, within arange between 10-80 μm or within a range between 20-80 μm. In order tofurther improve the deposition precision, the thickness t of thedeposition mask 20 may be set to be 40 μm or less, for example within arange between 10-40 μm or within a range between 20-40 μm.

In addition, as described above, the dimension r₂ of the second recess35 in this embodiment is smaller than a conventional one. Thus, when thedistance r₁ from the second surface 20 b of the deposition mask 20 up tothe connection portion 41 is relatively larger than the dimension r₂, arate of the deposition material adhering to the wall surface of thesecond recess 35 is considered to increase. In consideration of thispoint, in this embodiment, the distance r₁ from the second surface 20 bof the deposition mask 20 up up to the connection portion 41 ispreferably set within a range between 0-6 μm, i.e., 6 μm or less. Thefact that the distance r₁ is 0 μm means that the wall surface 36 of thesecond recess 35 does not exist, namely, the wall surface 31 of thefirst recess 30 reaches the second surface 21 b of the metal plate 21.

The plate thickness t of the metal plate 21 for manufacturing thedeposition mask 20 is not uniform and more or less varies. Thus, whenthe deposition mask 20 is manufactured by etching the metal plate 21under the same etching conditions, a shape of the through-hole 25 to beformed varies depending on the variation in plate thickness of the metalplate 21.

For example, when the plate thickness t of the metal plate 21 is smallerthan a target specification value, in the etching step, the first recess30 to be formed on the side of the first surface 21 a of the metal plate21 more promptly connects to the second recess 35 formed on the side ofthe second surface 21 b of the metal plate 21. In this case, in adirection where a distance between the through-portions 42 of theadjacent two through-holes 25 is relatively larger, the etching step mayterminate before the adjacent two first recesses 30 are connected toeach other in the direction. For example, as shown in FIG. 3, a distancebetween the through-portions 42 of the two through-holes 25 that areadjacent in a direction along the VI-VI line, i.e., in a directiondeviated from the arrangement direction of the through-holes 25, islarger than a distance between the through-portions 42 of the twothrough-holes 25 that are adjacent in a direction along the IV-IV lineor the V-V line, i.e., in the arrangement direction of the through-holes25. Thus, there is a possibility that, in the direction along the IV-IVline or the V-V line, the adjacent two first recesses 30 are connectedto each other upon termination of the etching step, but in the directionalong the VI-VI line, the adjacent two first recesses 30 are notconnected to each other upon termination of the etching step. Forexample, FIG. 8A shows a sectional view of the deposition mask 20 alongthe VI-VI line of FIG. 3 in which the two first recesses 30 that areadjacent in the direction along the VI-VI line are not connected to eachother. As shown in FIG. 8A, in this case, a portion 43 having a steepshape remains between the distal edges 32 of the wall surfaces 31 of theadjacent two first recesses 30. In the description below, the portion 43having a steep shape is also referred to a “top portion 43 a”.

The fact that there is the aforementioned top portion 43 a means thatthe height of the wall surface 31 of the first recess 30 of thethrough-hole 25 is large. Thus, in the example shown in FIG. 8A, anangle formed by the line L1, which passes through the connection portion41 and the distal edge 32 of the wall surface 31 of the first recess 30,with respect to the normal direction of the deposition mask 20, issmall. This means that the deposition material to be adhered to thesubstrate 92 is blocked by the wall surface 31 of the first recess 30 ofthe through-hole 25, i.e., shadow frequently occurs. Thus, theutilization efficiency of the deposition material lowers. In addition, adimensional precision of the deposition material to be adhered to thesubstrate is considered to be insufficient. Thus, it is preferable thatthe through-holes 25 are formed such that there exists no aforementionedtop portion 43 a, or otherwise that a width of the top portion 43 a is apredetermined value or less (e.g., 2 μm or less). The “width of the topportion” has the same meaning as a distance between the distal edges 32of the adjacent two first recesses 30.

Herebelow, there is described a relationship between an angle α formedby the line L1, which passes through the connection portion 41 and thedistal edge 32 of the wall surface 31 of the first recess 30, withrespect to the normal direction N of the deposition mask 20 (herebelowalso referred to a “Inclination angle α of the wall surface 31”), and awidth β of the top portion. As apparent from FIG. 8A, the greater thewidth β of the top portion becomes, the greater the inclination angle αof the wall surface 31 becomes. As a result, a large part of thedeposition material, coming along a direction that is largely inclinedas compared with the inclination angle α of the wall surface 31, isblocked by the wall surface 31 near the top portion. Namely, shadow islikely to occur. For example, in the deposition mask 20 for a displaydevice having a pixel density of 441 ppi, when a distance between thetwo through-holes 25 that are adjacent in the direction along the VI-VIline of FIG. 3 on the second surface 20 b is 39.1 μm, a distance betweenthe two through-holes 25 that are adjacent in the direction along theIV-IV line of FIG. 3 on the second surface 20 b is 27.6 μm, a dimensionof the through-hole 25 in the direction along the VI-VI line of FIG. 3on the second surface 20 b is 30.0 μm, and a distance r₁ from the secondsurface 20 b up to the connection portion 41 is 3 μm, and the width β ofthe top portion is 2.2 μm, the inclination angle α of the wall surface31 is 40°. When a minimum angle at which the deposition material comesis 40° or less, shadow is likely to occur. In this case, a value of thewidth β which can restrain occurrence of shadow may be 2 μm or less, forexample.

On the other hand, when the plate thickness t of the metal plate 21 islarger than a target specification value, in order to connect the firstrecess 30, which is to be formed on the side of the first surface 21 aof the metal plate 21, to the second recess 35, which is formed on theside of the second surface 21 b of the metal plate 21, an etching periodof time is required to be longer than a general one. In this case, asshown in FIG. 8B, an etching process for forming the first recess 30 onthe side of the first surface 21 a of the metal plate 21 proceeds morewidely than general. As a result, a maximum thickness Ta along thenormal direction of the elongated metal plate 64 in an area constitutingthe effective area 22 becomes smaller than a design value. Namely, anoverall thickness of the effective area 22 excessively reduces, wherebya lot of small deformations such as recesses may be generated in theeffective area.

Meanwhile, when an etching period of time is reduced in order torestrain generation of small deformations, the wall surface 31 of thefirst recess 30 merges with the wall surface 36 of the second recess 35at a position closer to the first surface 21 a. As apparent from FIGS.18 to 21 described later, a change rate of a cross-sectional area of thesecond recess 35 with respect to a position in the thickness directionof the metal plate 21 becomes larger as it is located closer to thefirst surface 21 a. Thus, the fact that the wall surface 31 of the firstrecess 30 merges with the wall surface 36 of the second recess 35 at aposition closer to the first surface 21 a means that a dimension of thethrough-portion 42 formed at the merged position is likely to vary.Thus, the reduction in etching period of time leads to a variation indimension of the through-portions 42.

Under such circumstances, in order to manufacture the deposition mask 20in which a variation in dimension of the through-holes is restrained, itis important to select a metal plate having a small thickness variation.

Next, an operation and an effect of this embodiment as structured aboveare described. Here, a method of manufacturing a metal plate for use inmanufacturing a deposition mask firstly. Then, a method of manufacturinga deposition mask by using the obtained metal plate is described.Thereafter, a method of depositing a deposition material onto asubstrate by using the obtained deposition mask.

(Method of Manufacturing Metal Plate)

A method of manufacturing a metal plate is firstly described withreference to FIG. 9(a). FIG. 9(a) is a view showing a step of rolling abase metal to obtain a metal plate having a desired thickness. FIG. 9(b)is a view showing a step of annealing the metal plate obtained by therolling step.

<Rolling Step>

As shown in FIG. 9(a), a base metal 55 formed of an invar material isprepared, and the base metal 55 is transported toward a rollingapparatus 56 including a pair of reduction rolls 56 a and 56 b along atransport direction shown by the arrow D1.

In the description below, the transport direction of the base metal 55and the metal plate during the rolling step is also referred to asrolling direction. The rolling direction is identical to a longitudinaldirection of an elongated metal plate obtained by the rolling step.

The base metal 55 having reached between the pair of reduction rolls 56a and 56 b is rolled by the pair of reduction rolls 56 a and 56 b. Thus,a thickness of the base metal 55 is reduced and is elongated along thetransport direction. As a result, an elongated metal plate 64 having athickness t can be obtained. As shown in FIG. 9(a), a winding body 62may be formed by winding up the elongated metal plate 64 around a core61. Although a value of the thickness t₀ is not particularly limited,the value is 80 μm or less or 40 μm or less, for example.

FIG. 9(a) merely shows the rolling step schematically, and a concretestructure and procedure for performing the rolling step are notspecifically limited. For example, the rolling step may include a hotrolling step in which the base metal is processed at a temperature notless than a recrystallization temperature of the invar materialconstituting the base metal 55, and a cold rolling step in which thebase metal is processed at a temperature not more than therecrystallization temperature of the invar material.

<Slitting Step>

After that, there may be performed a slitting step for slitting bothends of the elongated metal plate 64, which is obtained by the rollingstep, in the width direction thereof, over a range of 3-5 mm. Theslitting step is performed to remove a crack that may be generated onboth ends of the elongated metal plate 64 because of the rolling step.Due to the slitting step, it can be prevented that a breakage phenomenonof the elongated metal plate 64, which is so-called plate incision,occurs from the crack as a starting point.

<Annealing Step>

After that, in order to remove a remaining stress accumulated by therolling process in the elongated metal plate 64, as shown in FIG. 9(b),the elongated metal plate 64 is annealed by using an annealing apparatus57. As shown in FIG. 9(b), the annealing step may be performed while theelongated metal plate 64 is being pulled in the transport direction(longitudinal direction). Namely, the annealing step may be performed asa continuous annealing process while the elongated metal plate is beingtransported, instead of a batch-type annealing process. A duration ofthe annealing step is suitably set depending on a thickness of theelongated metal plate 64 and a reduction ratio thereof. For example, theannealing step is performed for 40-100 seconds within a temperaturerange of 400-600° C. The above “40-100 seconds” mean that it takes40-100 seconds for the elongated metal plate 64 to pass through a space,which is heated at a temperature within the above temperature range, inthe annealing apparatus 57.

Due to the annealing step, it is possible to obtain the elongated metalplate 64 of a thickness t, from which the remaining strain is removed toa certain extent. The thickness t is generally equal to a maximumthickness Tb in the peripheral area 23 of the deposition mask 20.

The elongated metal plate 64 having the thickness t may be made byrepeating the above rolling step, the slitting step and the annealingstep a plurality of times. FIG. 9(b) shows the example in which theannealing step is performed while the elongated metal plate 64 is beingpulled in the longitudinal direction. However, not limited thereto, theannealing step may be performed to the elongated metal plate 64 that iswound around the core 61. Namely, the batch-type annealing process maybe performed. When the annealing step is performed while the elongatedmetal plate 64 is wound around the core 61, the elongated metal plate 64may have a warping tendency corresponding to a winding diameter of thewinding body 62. Thus, depending on a winding diameter of the windingbody 62 and/or a material forming the base metal 55, it is advantageousto perform the annealing step while the elongated metal plate 64 isbeing pulled in the longitudinal direction.

<Cutting Step>

After that, there is performed a cutting step in which both ends of theelongated metal plate 64 in the width direction thereof are cut off overa predetermined range, so as to adjust the width of the elongated metalplate 64 into a desired width. In this manner, the elongated metal plate64 having a desired thickness and a desired width can be obtained.

<Inspection Step>

After that, there is performed an inspection step in which a thicknessof the thus obtained elongated metal plate 64 is inspected. FIG. 10 is aplan view of the elongated metal plate 64 obtained by the steps shown inFIGS. 9(a) and 9(b). In FIG. 10, a number of deposition masks 20, whichare cut out from the elongated metal plate 64 in a subsequent step, areshown by the dotted lines. As shown in FIG. 10, a plurality of thedeposition masks 20 extending in a direction in parallel with alongitudinal direction D1 of the elongated metal plate 64 are assignedto the elongated metal plate 64 both in the longitudinal direction D1 ofthe elongated metal plate 64 and in a width direction D1 thereof. Thus,when the plate thickness of the elongated metal plate 64 variesdepending on a position, thicknesses of the deposition masks 20 andshapes of the through-holes 25 individually differ from one another.Thus, a variation in plate thickness of the elongated metal plate 64 ispreferably small both in the longitudinal direction D1 and the widthdirection D2.

FIG. 10 shows an example in which five deposition masks 20 are assignedalong the width direction D2 of the elongated metal plate 64. From afirst side part 64 c of the elongated metal plate 64 toward a secondside part 64 d thereof, the five deposition masks 20 are indicated bythe symbols 20 _(ak), 20 _(bk), 20 _(ck), 20 _(dk) and 20 _(ek) (k is agiven natural number) in this order. In FIG. 11B, plate thicknesses ofthe elongated metal plate 64, which are located at positionscorrespondingly to the deposition masks 20 _(ak), 20 _(bk), 20 _(ck), 20_(dk) and 20 _(ek) are indicated by the symbols t_(a), t_(b), t_(c)t_(d) and t_(e). The plate thickness t_(c) of a part of the elongatedmetal plate 64, to which the deposition mask 20 _(ck), which iscentrally positioned in the five deposition masks 20 arranged in thewidth direction D2, is assigned, corresponds to a plate thickness of theelongated metal plate 64 at a central portion in the width direction D2.

In the inspection step, there is firstly performed a first inspectionstep in which a plate thickness of the elongated metal plate 64 ismeasured along the longitudinal direction D1 at many points. The firstinspection step may be performed during the rolling step, or may beperformed after the rolling step. When the first inspection step isperformed after the rolling step, the first inspection step may beperformed by a measuring device provided on the same production line asthat of the rolling step, or may be performed by a measuring deviceprovided on a different line from that of the rolling step.

Although a measuring method is not specifically limited, it is possibleto employ a method in which the elongated metal plate 64 is irradiatedwith an X-ray, and a fluorescent X-ray emitted from the elongated metalplate 64 is measured. This method takes advantage of the fact that anintensity of a fluorescent X-ray to be measured depends on an amount ofan element constituting the elongated metal plate 64, and thus on aplate thickness of the elongated metal plate 64. Such a measuring methodusing an X-ray is utilized when a film thickness of a plating film ismeasured.

Although a measurement point is not specifically limited, a platethickness of the elongated metal plate 64 at the central portion in thewidth direction D2, i.e., the plate thickness t_(c) shown in FIG. 11 ismeasured along the longitudinal direction at many points, for example.Thus, an average value and a standard deviation of plate thicknesses ofthe elongated metal plate 64 in the longitudinal direction D1 can becalculated. An interval between the measurement points of the elongatedmetal plate 64 in the longitudinal direction D1 is within a range of50-500 μm, for example.

As described below, selection of an elongated metal plate 64 based on avariation in plate thickness of the elongated metal plate 64 iseffective when an average value of plate thicknesses of the elongatedmetal plate 64 in the longitudinal direction D1 is within a ±3% rangearound a predetermined value. Namely, in a case where an average valueof plate thicknesses of the elongated metal plate 64 in the longitudinaldirection D1 deviates from the ±3% range around a predetermined value,it may be impossible to manufacture a deposition mask 20 of a highquality, even if the elongated metal plate 64 satisfies thebelow-described conditions (1) and (2). Thus, when the first inspectionstep is performed during the rolling step, as described above, afeedback control may be performed during the rolling step such that anaverage value of plate thicknesses of the elongated metal plate 64 inthe longitudinal direction D1 is included within a ±3% range around apredetermined value. The “predetermined value” is a so-called “designvalue” or “specification value”, which is a reference value when theelongated metal plate 64 and the metal plate 21 are delivered to aclient.

As described in the below examples, a predetermined value (design value,specification value) of a plate thickness of the elongated metal platemay be 20 μm, 25 μm, 40 μm and so on. When these predetermined valuesare employed, selection of an elongated metal plate 64 based on avariation in plate thickness of the elongated metal plate 64 accordingto this embodiment is effective respectively when an average value ofplate thicknesses of the elongated metal plate 64 in the longitudinaldirection D1 is within a ±3% range around 20 μm, a ±3% range around 25μm, and a ±3% range around 40 μm.

A value called design value or specification value of a plate thicknessof the elongated metal plate 64 is not a technical matter but a matterbased on a transaction contract. Thus, such a value cannot be calculatedmerely by observing the elongated metal plate 64 itself. On the otherhand, a selection effectiveness of an elongated metal plate 64 based onthe below-described conditions (1) and (2) according to this embodimentdoes not depend on a design value or a specification value itself of aplate thickness of the elongated metal plate 64. This is because theselection of an elongated metal plate 64 according to this embodimentspecifies a variation in plate thickness in one elongated metal plate64, in order for obtaining through-holes each 25 having a suitable shapeand a dimension, when the through-holes 25 are formed under a certainetching condition. When the through-holes 25 are formed by etching, itis possible to cope with a given plate thickness by changing an etchingcondition. Thus, even when a design value or a specification value of aplate thickness of the elongated metal plate 64 is unknown, theeffectiveness of the selection of an elongated metal plate 64 accordingto this embodiment can be judged. For example, in a plurality ofelongated metal plates 64 shipped from a metal plate manufacturer and aplurality of elongated metal plates 64 owned by a deposition maskmanufacturer, when an average value variation in plate thickness of theelongated metal plates 64 in the longitudinal direction D1 is within a±3% range, it can be said that the selection according to thisembodiment can be effectively applied.

Next, there is performed a second inspection step in which the platethickness of the elongated metal plate 64 is measured along the widthdirection D2 at many points. A method of measuring the plate thicknessin the second inspection step is not specifically limited. Similarly tothe first inspection step, it is possible to employ a method in whichthe elongated metal plate 64 is irradiated with an X-ray and afluorescent X-ray emitted from the elongated metal plate 64 is measured.Alternatively, a contact-type measuring method may be employed. As ameasuring device for performing a contact-type measuring method, MT1271(Length Gauges) manufactured by Heidenhain Co. can be used.

A measurement point is also not specifically limited. In a predeterminedposition, a plate thickness of the elongated metal plate 64 is measuredalong the width direction D2 of the elongated metal plate 64 at manypoints. Thus, an average value and a standard deviation of platethicknesses of the elongated metal plate 64 in the width direction D2can be calculated. An interval between the measurement points of theelongated metal plate 64 in the width direction D2 is within a range of5-50 μm, for example.

The length of the elongated metal plate 64 in the width direction D2 issignificantly smaller than the length thereof in the longitudinaldirection D1. Thus, as compared with the measurement in the longitudinaldirection D1, it is difficult to increase the number of measurementpoints in the measurement in the width direction D2. As a result, anaccuracy of a calculated standard deviation is considered to lower. Inconsideration of this point, a standard deviation of plate thicknessesof the elongated metal plate 64 in the width direction D2 may be astandard deviation that is calculated based on plate thicknesses of theelongated metal plate 64, which are measured at intersections betweenimaginary lines the number of which is m (m is a natural number of 2 ormore), each extending on the elongated metal plate 64 in thelongitudinal direction D1, and an imaginary line(s) the number of whichis n (n is a natural number of 1 or more), each extending on theelongated metal plate 64 in the width direction D2. For example, thenumber m may be 9, while the number n may be 3. Thus, the number ofmeasurement points can be sufficiently increased, whereby a standarddeviation can be precisely calculated. The imaginary lines the number ofwhich is m, each extending on the elongated metal plate 64 along thelongitudinal direction D1, and the imaginary lines the number of whichis n, each extending on the elongated metal plate 64 along the widthdirection D2, are drawn in a predetermined area of the elongated metalplate 64. For example, they are drawn in a predetermined area defined byan area of 500 mm in the longitudinal direction D1 and by an area of 500mm in the width direction D2.

The aforementioned second inspection step in which the plate thicknessof the elongated metal plate 64 in the width direction D2 may beperformed during the rolling step, or may be performed after the rollingstep. When the second inspection step is performed after the rollingstep, the elongated plate metal 64, which is cut over a predeterminedlength, may be subjected to the second inspection step.

After a plate thickness of the elongated metal plate 64 has beenmeasured at respective positions, the selection based on a variation inplate thickness is performed to the elongated metal plates 64 whoseaverage value of the plate thicknesses in the longitudinal direction D1is within a ±3% range around a predetermined value. Herein, theselection of an elongated metal plate 64 is performed such that only anelongated metal plate 64 which satisfies all the below conditions (1)and (2) is used in a below-described step of manufacturing thedeposition masks 20.

(1) When an average value of plate thicknesses of the elongated metalplate 64 in the longitudinal direction (rolling direction) D1 isrepresented as A, and a value obtained by multiplying a standard valueof the plate thicknesses of the elongated metal plate 64 in thelongitudinal direction D1 by 3 is represented as B, (B/A)×100(%) is 5%or less; and(2) When a value obtained by multiplying a standard deviation of platethicknesses of the elongated metal plate 64 in the width direction by 3is represented as C, and a value of a plate thickness of the elongatedmetal plate 64 at the central portion in the width direction D2, whichis obtained when the plate thicknesses of the elongated metal plate 64are measured along the width direction D2 in order to calculate astandard deviation of the plate thicknesses of the elongated metal plate64 in the width direction D2, is represented as X, (C/X)×100(%) is 3% orless.

The aforementioned conditions (1) and (2) are respectively describedbelow.

The aforementioned condition (1) is a condition for restraining that thedimension of a through-hole 25 of the plurality of deposition masks 20assigned along the longitudinal direction D1 of the elongated metalplate 64 varies depending on an assigned position. The aforementionedcondition (2) is a condition for restraining that the dimension of athrough-hole 25 of the plurality of deposition masks 20 assigned alongthe width direction D2 of the elongated metal plate 64 varies dependingon an assigned position.

Generally, in the longitudinal direction D1 of the elongated metal plate64, it is difficult to estimate a variation tendency (degree, cycle,etc.) of the plate thickness of the elongated metal plate 64. On theother hand, in the width direction D2 of the elongated metal plate 64, avariation tendency of the plate thickness of the elongated metal plate64 is considered to be more or less uniform. For example, FIG. 11B showsthat the plate thickness t_(c) at the central portion in the widthdirection D2 is larger than the plate thickness t_(a) near the firstside part 64 c and the plate thickness t_(e) near the second side part64 d. When the plate thickness varies in the width direction D2, it canbe restrained that the through-holes 25 formed in positions of differentplate thicknesses differ in dimension and shape, by setting an etchingcondition in consideration of the variation. For example, in the exampleshown in FIG. 11B, by making smaller a pressure of an etchant, which isinjected from a predetermined spray toward the elongated metal plate 64for forming the first recess 30 of the through-hole 25 near the firstside part 64 c or near the second side part 64 d, than a pressure of anetchant which is to be injected toward the central portion in the widthdirection D2, the difference in dimension and shape of the through-holes25 can be reduced. The aforementioned condition (2) may be determinedtaking such an etching condition adjustment into consideration. Theetching condition that can be adjusted depending on a variation mayinclude an oscillating position of a spray, an oscillating angle thereofand an oscillating speed, in addition to the above etchant pressure(spray pressure).

(Method of Manufacturing Deposition Mask)

Next, a method of manufacturing the deposition mask 20 by using theelongated metal plate 64 selected as described above is described withreference to FIGS. 12 to 21. In the below-described method ofmanufacturing the deposition mask 20, as shown in FIG. 12, the elongatedmetal plate 64 is supplied, the through-holes 25 are formed in theelongated metal plate 64, and the elongated metal plate 64 are severedso that the deposition masks 20 each of which is formed of thesheet-like metal plate 21 are obtained.

To be more specific, the method of manufacturing a deposition mask 20includes a step of supplying an elongated metal plate 64 that extendslike a strip, a step of etching the elongated metal plate 64 using thephotolithographic technique to form a first recess 30 in the elongatedmetal plate 64 from the side of a first surface 64 a, and a step ofetching the elongated metal plate 64 using the photolithographictechnique to form a second recess 35 in the elongated metal plate 64from the side of a second surface 64 b. When the first recess 30 and thesecond recess 35, which are formed in the elongated metal plate 64,communicate with each other, the through-hole 25 is made in theelongated metal plate 64. In the example shown in FIGS. 13 to 21, thestep of forming the second recess 35 is performed before the step offorming the first recess. In addition, between the step of forming thesecond recess 35 and the step of forming the first recess 30, there isfurther provided a step of sealing the thus made second recess 35.Details of the respective steps are described below.

FIG. 12 shows a manufacturing apparatus 60 for making the depositionmasks 20. As shown in FIG. 12, the winding body 62 having the core 61around which the elongated metal plate 64 is wound is firstly prepared.By rotating the core 61 to unwind the winding body 62, the elongatedmetal plate 64 extending like a strip is supplied as shown in FIG. 12.After the through-holes 25 are formed in the elongated metal plate 64,the elongated metal plate 64 provides the sheet-like metal plates 21 andfurther the deposition masks 20.

The supplied elongated metal plate 64 is transported by the transportrollers 72 to an etching apparatus (etching means) 70. The respectiveprocesses shown in FIGS. 13 to 21 are performed by means of the etchingmeans 70. In this embodiment, a plurality of the deposition masks 20 isassigned in the width direction of the elongated metal plate 64. Namely,the deposition masks 20 are made from an area occupying a predeterminedposition of the elongated metal plate 64 in the longitudinal direction.In this case, it is preferable that the deposition masks 20 are assignedto the elongated metal plate 64 such that the longitudinal direction ofeach deposition mask 20 corresponds to the rolling direction D1 of theelongated metal plate 64.

As shown in FIG. 13, a negative-type photosensitive resist material isfirstly applied to the first surface 64 a (lower surface in the sheetplane of FIG. 11) and the second surface 64 b of the elongated metalplate 64, so that resist films 65 c and 65 d are formed on the elongatedmetal plate 64.

Then, exposure masks 85 a and 85 b which do not allow light to transmitthrough areas to be removed of the resist films 65 c and 65 d areprepared. As shown in FIG. 12, the masks 85 a and 85 d are located onthe resist films 65 c and 65 d. For example, glass dry plates which donot allow light to transmit through the areas to be removed from theresist films 65 c and 65 d are used as the exposure masks 85 a and 85 d.Thereafter, the exposure masks 85 a and 85 b are sufficiently broughtinto tight contact with the resist films 65 c and 65 d by vacuumbonding.

A positive-type photosensitive resist material may be used. In thiscase, there is used an exposure mask which allows light to transmitthrough an area to be removed of the resist film.

After that, the resist films 65 c and 65 d are exposed through theexposure masks 85 a and 85 b. Further, the resist films 65 c and 65 dare developed (developing step) in order to form an image on the exposedresist films 65 c and 65 d. Thus, as shown in FIG. 13, a resist pattern(also referred to simply as resist) 65 a can be formed on the firstsurface 64 a of the elongated metal plate 64, while a resist pattern(also referred to simply as resist) 65 b can be formed on the secondsurface 64 b of the elongated metal plate 64. The developing step mayinclude a resist heating step for increasing a hardness of the resistfilms 65 c and 65 d.

Then, as shown in FIG. 16, by using an etchant (e.g., ferric chloridesolution), the elongated metal plate 64 is etched from the side of thesecond surface 64 b, with the resist pattern 65 d formed on theelongated metal plate 64 serving as a mask. For example, the etchant isejected from a nozzle, which is disposed on the side facing the secondsurface 64 b of the transported elongated metal plate 64, toward thesecond surface 64 b of the elongated metal plate 64 through the resistpattern 65 b. As a result, as shown in FIG. 16, areas of the elongatedmetal plate 64, which are not covered with the resist pattern 65 b, areeroded by the etchant. Thus, a lot of second recesses 35 are formed inthe elongated metal plate 64 from the side of the second surface 64 b.

After that, as shown in FIG. 17, the formed second recesses 35 arecoated with a resin 69 resistant to the etching liquid. Namely, thesecond recesses 35 are sealed by the resin 69 resistant to the etchingliquid. In the example shown in FIG. 17, a film of the resin 69 isformed to cover not only the formed second recesses 35 but also thesecond surface 64 b (resist pattern 65 b).

Then, as shown in FIG. 18, the elongated metal plate 64 is subjected tothe second etching process. In the second etching process, the elongatedmetal plate 64 is etched only from the side of the first surface 64 a,so that the first recess 30 is gradually formed from the side of thefirst surface 64 a. This is because the elongated metal plate 64 iscoated with the resin 69 resistant to the etching liquid, on the side ofthe second surface 64 b. Thus, there is no possibility that the shapesof the second recesses 35, which have been formed to have a desiredshape by the first etching process, are impaired.

The erosion by the etching process takes place in a portion of theelongated metal plate 64, which is in contact with the etching liquid.Thus, the erosion develops not only in the normal direction (thicknessdirection) of the elongated metal plate 64 but also in a direction alongthe plate plane of the elongated metal plate 64. Thus, as shown in FIG.19, with the development of etching in the normal direction of theelongated metal plate 64, not only the first recess 30 becomescontinuous with the second recess 35, but also two first recesses 30,which are formed at positions facing two adjacent holes 66 a of theresist pattern 65 a, are merged with each other on a reverse side of abridge portion 67 a positioned between the two holes 66 a.

As shown in FIG. 20, the etching from the side of the first surface 64 aof the elongated metal plate 64 further develops. As shown in FIG. 20, amerged portion 43 where the two adjacent first recesses 30 are mergedwith each other is separated from the resist pattern 65 a, and theerosion by the etching process develops also in the normal direction(thickness direction) of the metal plate 64 at the merged portion 43below the resist pattern 65 a. Thus, the merged portion 43, which issharpened toward the one side along the normal direction of thedeposition mask, is etched from the one side along the normal directionof the deposition mask, so that the merged portion 43 is chamfered asshown in FIG. 20. Thus, the inclination angle 91, which is defined bythe wall surface 31 of the first recess 30 with respect to the normaldirection of the deposition mask, can be increased.

In this manner, the erosion of the first surface 64 a of the elongatedmetal plate 64 by the etching process develops in the whole area formingthe effective area 22 of the elongated metal plate 64. Thus, a maximumthickness Ta along the normal direction of the elongated metal plate 64,in the area forming the effective area 22, becomes smaller than amaximum thickness Tb of the elongated metal plate 64 before beingetched.

When the etching process from the side of the first surface 64 a of theelongated metal plate 64 develops by a preset amount, the second etchingprocess to the elongated metal plate 64 is ended. At this time, thefirst recess 30 extends in the thickness direction of the elongatedmetal plate 64 up to a position where it reaches the second recess 35,whereby the through-hole 25 is formed in the elongated metal plate 64 bymeans of the first recess 30 and the second recess 35 that are incommunication with each other.

In the second etching step for forming the first recess 30 in the firstsurface 64 a of the elongated metal plate 64, the etching condition maybe differed depending on a position of the elongated metal plate 64 inthe width direction D2. For example, a position of the nozzle forinjecting the etchant (a distance from a distal end up to the firstsurface 64 a of the elongated metal plate 64) and/or a pressure of theetchant to be injected may be differed depending on a position of theelongated metal plate 64 in the width direction D2. Thus, even when theplate thickness of the elongated metal plate 64 varies in the widthdirection D2, it can be restrained that the through-holes 25 formed inpositions of different plate thickness differ in dimension and shape.

After that, as shown in FIG. 21, the resin 69 is removed from theelongated metal plate 64. For example, the resin 69 can be removed byusing an alkali-based peeling liquid. When the alkali-based peelingliquid is used, as shown in FIG. 21, the resist patterns 65 a and 65 bare removed simultaneously with the removal of the resin 69. However,after the removal of the resin 69, the resist patterns 65 a and 65 b maybe removed separately from the resin 69.

The elongated metal plate 64 having a lot of through-holes 25 formedtherein is transported to a cutting apparatus (cutting means) 73 by thetransport rollers 72, 72 which are rotated while sandwichingtherebetween the elongated metal plate 64. The above-described supplycore 61 is rotated through a tension (tensile stress) that is applied bythe rotation of the transport rollers 72, 72 to the elongated metalplate 64, so that the elongated metal plate 64 is supplied from thewinding body 62.

Thereafter, the elongated metal plate 64 in which a lot of recesses 30,35 are formed is cut by the cutting apparatus (cutting means) 73 to havea predetermined length and a predetermined width, whereby the sheet-likemetal plates 21 having a lot of through-holes 25 formed therein can beobtained.

In this manner, the deposition mask 20 formed of the metal plate 21 witha lot of through-holes 25 formed therein can be obtained. According tothis embodiment, the first surface 21 a of the metal plate 21 is etchedover the whole effective area 22. Thus, the thickness of the effectivearea 22 of the deposition mask 20 can be reduced, and the outline of theportion 43, where the distal edges 32 of the wall surfaces 31 of the twofirst recesses 30 formed on the side of the first surface 21 a aremerged with each other, can have a chamfered shape. As a result, theaforementioned angle θ1 can be increased, to thereby improve theutilization efficiency of the deposition material and the positionalprecision of deposition.

In addition, according to this embodiment, due to the aforementionedconditions (1) and (2), in the step of manufacturing the depositionmasks 20, there is used the elongated metal plate 64 whose variation inplate thickness is a predetermined value or less both in thelongitudinal direction D1 and the width direction D2. Thus, it can berestrained that the dimension of the through-hole 25 of the depositionmask 20 varies depending on a position of the elongated metal plate 64to which the deposition mask is assigned. Thus, the high-qualitydeposition masks 20 can be stably manufactured.

(Deposition Method)

Next, a method of depositing the deposition material onto the glasssubstrate 92 by using the obtained deposition mask 20 is described. Asshown in FIG. 2, the deposition mask 20 is firstly brought into tightcontact with the substrate 92. At this time, the second surface 20 b ofthe deposition mask 20 may be brought into right contact with thesurface of the substrate 92. In addition, as shown in FIG. 1, thedeposition masks 20 are attached to the frame 15 in a taut state, sothat the surface of each deposition mask 20 is in parallel with thesurface of the glass substrate 92. Thereafter, by heating the depositionmaterial 98 in the crucible 94, the deposition material 98 is evaporatedor sublimated. The evaporated or sublimated deposition material 98adheres to the glass substrate 92 through the through-holes 25 in thedeposition masks 20. As a result, a layer of the deposition material 98is formed on the surface of the glass substrate 92 in a desired patterncorresponding to the positions of the through-holes 25 of the depositionmasks 20.

According to this embodiment, due to the aforementioned conditions (1)and (2), a variation in dimension of the through-holes 25 of thedeposition mask 20 is restrained. Thus, when pixels of an organic ELdisplay device is formed by a deposition process, a dimensionalprecision of the pixels of the organic EL display device can beimproved. Thus, a highly fine organic EL display device can bemanufactured.

In this embodiment, the first surface 21 a of the metal plate 21 isetched over the whole effective area 22. However, not limited thereto,the first surface 21 a of the metal plate 21 may be etched only over apart of the effective area 22.

In addition, in this embodiment, a plurality of the deposition masks 20is assigned in the width direction of the elongated metal plate 64. Inaddition, in the deposition step, the plurality of deposition masks 20is mounted on the frame 15. However, not limited thereto, as shown inFIG. 22, there may be used deposition masks 20 having a plurality of theeffective areas 22 arranged like a grid along both the width directionand the longitudinal direction of the metal plate 21. Also in this case,by using the elongated metal plate 64 that satisfies the aforementionedconditions (1) and (2), it can be restrained that the dimension of thethrough-hole 25 of the deposition mask 20 varies depending on a positionon the elongated metal plate 64.

In the above description, the inspection step of inspecting theelongated metal plate 64 based on the aforementioned conditions (1) and(2) is performed for the selection of an elongated metal plate 64.However, the method of utilizing the conditions (1) and (2) is notlimited to the above embodiment.

For example, the aforementioned conditions (1) and (2) may be utilizedfor optimizing a condition for manufacturing the elongated metal plate64, such as a rolling condition and an annealing condition.Specifically, the conditions (1) and (2) may be used for the followingoperation. Namely, elongated metal plates 64 are manufactured undervarious rolling conditions and various annealing conditions, and platethicknesses of the obtained elongated metal plates 64 are measured.Then, by comparing the measurement results with the conditions (1) and(2), a suitable rolling condition and a suitable annealing conditionthat satisfy the conditions (1) and (2) are determined. In this case, itis not necessary that all the elongated metal plates 64 obtained in theactual manufacturing step are subjected to the selection based on theconditions (1) and (2). For example, only some of the elongated metalplates 64 may be subjected to a sampling inspection related to theconditions (1) and (2). Alternatively, once a manufacturing conditionsuch as a rolling condition and an annealing condition has beendetermined, the inspection related to the conditions (1) and (2) may notbe performed at all. In addition, when the elongated metal plate 64 ismanufactured by utilizing a plating process, the conditions (1) and (2)may be utilized for determining a suitable plating condition.

In addition, in the above embodiment, a metal plate having a desiredthickness is obtained by rolling a base metal. However, the way ofobtaining a metal plate is not limited to rolling method. A metal platehaving a desired thickness may be manufactured by a film forming steputilizing a plating process. In the film forming step, as shown in FIG.37, for example, while a drum 112 made of stainless, which is partiallyimmersed in a plating liquid 11 to function as a first electrode, isrotated opposedly to a second electrode 113, a plating film is formed ona surface of the drum 112. By peeling the plating film, the elongatedmetal plate 64 can be manufactured in a roller-to-roller manner. When ametal plate is manufactured of an iron alloy containing nickel, amixture solution of a solution containing a nickel compound and asolution of an iron compound may be used as a plating liquid. Forexample a mixture solution of a solution containing nickel sulfamate anda solution containing iron sulfamate may be used, for example. Anadditive such as malonic acid or saccharin may be contained in theplating liquid.

The above annealing step may be performed to the metal plate obtained byutilizing a plating process. In addition, after the annealing step,there may be performed the aforementioned cutting step for cutting offboth ends of the metal plate, so as to adjust the width of the metalplate into a desired width.

Also when a metal plate is manufactured by utilizing a plating process,similarly to the aforementioned embodiment, the deposition mask 20having a plurality of the through-holes 25 formed therein can beobtained by subsequently performing a step of forming the resistpatterns 65 a and 65 b and a step of etching the first surface and thesecond surface of the metal plate.

Also when a metal plate is manufactured by utilizing a plating process,similarly to the case in which a metal plate is manufactured by rollinga base metal, a plate thickness t of the metal plate is not uniform, andmore or less varies. For example, the thickness of the metal plate mayvary depending on a position, because of a variation in shape andposition of an electrode for depositing a plating film (such as theabove drum) and of flowage of plating liquid. Thus, in accordance withthe variation in plate thickness of the metal plate, the shape of thethrough-hole 25 to be formed is considered to vary. Thus, also when ametal plate is manufactured by utilizing a plating process, selection ofmetal plate and manufacturing conditions can be optimized by utilizingthe aforementioned conditions (1) and (2).

Similarly to the case in which a metal plate is manufactured by rollinga base metal, when a metal plate is manufactured by utilizing a platingprocess, the aforementioned conditions (1) and (2) are effective when anaverage value of the plate thicknesses of the elongated metal plate 64in the longitudinal direction D1 is within a ±3% range around apredetermined value. Thus, also when a plating step in which a metalplate is manufactured by utilizing a plating process, a feedback controlmay be performed such that an average value of the plate thicknesses ofthe elongated metal plate 64 in the longitudinal direction is includedwithin a ±3% range around a predetermined value, as described later.

An amount of a metal deposited by an electrolytic plating process isdetermined depending on a current density of a current flowing throughan electrode, a plating liquid concentration, and a plating period oftime. Thus, by maintaining constant a current density and a platingliquid concentration, for example, a variation in amount of metal to bedeposited per unit time can be restrained, so that an average value ofthe plate thicknesses of the elongated metal plate 64 in thelongitudinal direction D1 can be within a ±3% range around apredetermined value. As a method of maintaining constant a platingliquid concentration, it is possible to employ a feedback control inwhich a plating liquid concentration is measured, and new plating liquidis added based on a measurement result. It goes without saying that afeedback control based on another measurement result can be suitablyemployed.

EXAMPLES

Next, the present invention is described in more detail based onexamples, and the present invention is not limited to the belowdescription of the examples unless the present invention departs fromits spirit.

Example 1

(11^(th) Winding Body and 11^(th) Mask)

There was conducted a test for confirming that the aforementionedcondition (1) is effective. To be specific, a base metal made of an ironalloy containing nickel was prepared. Then, by performing theabove-described rolling step, the slitting step, the annealing step andthe cutting step were performed to the base metal, a winding body(11^(th) winding body) formed of a wound elongated metal plate wasmanufactured. A target specification value of a plate thickness of theelongated metal plate was 20 μm.

To be specific, there were performed the first rolling step in which thefirst hot rolling step and the first cold rolling step were performed inthis order, then the first slitting step in which both ends of theelongated metal plate were cut over a range not less than 3 mm and notmore than 5 mm, and the first annealing step in which the elongatedmetal plate was continuously annealed at a temperature range between400-600° C. for 40-100 seconds. Further, the elongated metal platehaving been subjected to the first annealing step was subjected to thesecond rolling step including the second cold rolling step, then thesecond slitting step in which both ends of the elongated metal platewere cut over a range not less than 3 mm and not more than 5 mm, and thesecond annealing step in which the elongated metal plate wascontinuously annealed at a temperature range between 400-600° C. for40-100 seconds. Thus, the elongated metal plate having a length of about400 m and a width of about 600 mm was obtained. After that, there wasperformed a cutting step in which both ends of the elongated metal platein the width direction were cut off over a predetermined range, wherebythe width of the elongated metal plate was finally adjusted to apredetermined width, specifically, a width of 500 mm.

In the above cold rolling step, a pressure adjustment using a backuproller was performed. To be specific, a shape and a pressure of a backuproller of a rolling machine were adjusted such that the elongated metalplate had a symmetric shape in the right and left direction. The coldrolling step was performed while cooling the elongated metal plate usingrolling oil such as coal oil. After the cold rolling step, there wasperformed a cleaning step in which the elongated metal plate was cleanedwith a hydrocarbon-based cleaning liquid. After the cleaning step, theabove-described slitting step was performed.

Thereafter, the plate thickness of the elongated metal plate at thecentral portion in the width direction was measured along thelongitudinal direction at many points. An interval between themeasurement points of the elongated metal plate 64 in the longitudinaldirection D1 was within a range between 50-500 mm. As a measuringapparatus, there was used a wavelength-dispersive type XRF apparatuswhich was configured to in-line measure the plate thickness of theelongated metal plate in a production line where the rolling step wasperformed. An average value (represented sometimes as a symbol Aherebelow) of the plate thicknesses of the elongated metal plate in thelongitudinal direction was 20.0 μm and a value (represented sometimes asa symbol 3σ or B) obtained by multiplying a standard deviation of theplate thicknesses of the elongated metal plate in the longitudinaldirection by 3 was 0.2 μm.

Next, a deposition mask 20 (referred to as 11^(th) mask herebelow)having a number of through-holes formed therein was manufactured byusing the elongated metal plate of the above 11^(th) winding body. To bespecific, five 11^(th) masks were assigned along the width direction D2of the elongated metal plate and a number of (at least ten) 11^(th)masks were assigned along the longitudinal direction D1 of the elongatedmetal plate, whereby at least fifty 11^(th) masks were manufactured. Atarget specification value of a dimension of the through-hole in each11^(th) mask was 30 μm×30 μm.

Next, dimensions of the through-holes in ten 11^(th) masks, which wereassigned to the central portion in the width direction D2 of theelongated metal plate, out of a lot of manufactured 11^(th) masks, wasmeasured. The number of measurement points at which the dimension of thethrough-hole in each 11^(th) mask 20 was 45. To be specific, as shown inFIG. 23, in each of the five effective areas arranged in thelongitudinal direction of the 11^(th) mask (deposition mask 20), thedimension of the through-hole 25 was measured at 9 points. As shown inFIG. 23, for example, the nine measurement points 101 were uniformlydistributed in the central portion and the end portion of the effectivearea 22.

In the method of measuring the dimension of the through-hole, the11^(th) mask and a substrate were firstly prepared, and light wasemitted from a first surface side to the 11^(th) mask. At this time, alight irradiation area, which was irradiated with light having passedthrough the through-hole of the 11^(th) mask, was formed on thesubstrate. A dimension of the light irradiation area was measured as thedimension of the through-hole.

Dimensions of the through-holes in the ten 11^(th) masks were measuredat 450 points in total, and a variation in dimension of thethrough-holes (a value obtained by multiplying a standard deviation ofthe dimensions by 3) was calculated. The variation in dimension of thethrough-holes was 1.5 μm.

(12^(th) to 17^(th) Winding Bodies and 12^(th) to 17^(th) Masks)

Similarly to the case of the 11^(th) winding body, 12^(th) to 17^(th)winding bodies were manufactured using a base metal made of an ironalloy containing nickel. A target specification value of elongated metalplate of the 12^(th) to 17^(th) winding bodies was 20 μm. Similarly tothe case of the 11^(th) winding body, a plate thickness of the elongatedmetal plate at the central portion in the width direction was measuredalong the longitudinal direction at many points. Further, similarly tothe case of the 11^(th) winding body, deposition masks (referred to as12^(th) to 17^(th) mask herebelow) having a lot of through-holes formedtherein were manufactured by using the elongated metal plates of the12^(th) to 17^(th) winding bodies. In addition, similarly to the case ofthe 11^(th) mask, the dimensions of the through-holes were measured.FIG. 24(a) shows an average value A and a variation B in plate thicknessof the elongated metal plates of the 12^(th) to 17^(th) winding bodiesin the longitudinal direction, in addition to an average value A and avariation B in plate thickness of the elongated metal plate of the11^(th) winding body in the longitudinal direction. In addition, FIG.25(a) shows a variation in dimension of through-holes in the 12^(th) to17^(th) masks, in addition to a variation in dimension of thethrough-holes in the 11^(th) mask.

As shown in FIG. 24(a), the 11^(th) to 15^(th) winding bodies satisfiedthe aforementioned condition (1). Namely, a percentage of a valueobtained by dividing the variation (A) in plate thickness in thelongitudinal direction by the average value A of the plate thicknessesin the longitudinal direction was 5% or less. On the other hand, the16^(th) and the 17^(th) winding bodies did not satisfy theaforementioned condition (1). In addition, as shown in FIG. 25(a), inthe 11^(th) to the 15^(th) masks obtained from the elongated metalplates of the 11^(th) to 15^(th) winding bodies, a variation indimension of the through-holes was restrained to 2.0 μm or less. On theother hand, in the 16^(th) and the 17^(th) masks obtained from theelongated metal plates of the 16^(th) and the 17^(th) elongated metalplates, a variation in dimension of the through-holes was over 2.0 μm.

In order to manufacture an organic EL display device having a pixeldensity of 450 ppi or more, a variation in dimension of thethrough-holes in the deposition mask 20 is preferably 2.0 μm or less. Ascan be understood from FIGS. 24(a) and 25(a), in this embodiment, aslong as the aforementioned condition (1) was satisfied, it was possibleto manufacture a deposition mask having through-holes whose variation indimension in the longitudinal direction is restrained in an allowablerange. Namely, it can be considered that the aforementioned condition(1) is an important judging method of selecting an elongated metalplate.

Example 2

Similarly to the case of Example 1, 21^(st) to 27^(th) winding bodieswere manufactured, except that a target specification value of a platethickness of an elongated metal plate was 25 μm. In addition, similarlyto the case of Example 1, 21^(st) to 27^(th) masks were manufactured byusing the elongated metal plates of the 21^(st) to the 27^(th) windingbodies, except that a target specification value of a dimension of athrough-hole was 40 μm×40 μm. In addition, similarly to the case ofExample 1, a plate thickness of the elongated metal plates of the21^(st) to the 27^(th) winding bodies at the central portion in thewidth direction was measured along the longitudinal direction at manypoints. In addition, similarly to the case of Example 1, dimensions ofthe through-holes in the 21^(st) to the 27^(th) mask were measured.

FIG. 24(b) shows an average value A and a variation Bin plate thicknessin the longitudinal direction of the elongated metal plates of the21^(st) to the 27^(th) elongated metal plates. In addition, FIG. 25(b)shows a variation in dimension of the through-holes in the 21^(st) tothe 27^(th) masks.

As shown in FIG. 24(b), the 21^(st) to the 25^(th) winding bodiessatisfied the aforementioned condition (1). On the other hand, the26^(th) and the 27^(th) winding bodies did not satisfy theaforementioned condition (1). In addition, as shown in FIG. 25(b), inthe 21^(st) to the 25^(th) masks obtained from the elongated metalplates of the 21^(st) to the 25^(th) winding bodies, a variation indimension of the through-holes was restrained to 2.0 μm or less. On theother hand, in the 26^(th) and the 27^(th) masks obtained from theelongated metal plates of the 26^(th) and the 27^(th) elongated metalplates, a variation in dimension of the through-holes was over 2.0 μm.Namely, also when the target specification value of the plate thicknessof the elongated metal plate is 25 μm, it can be said that theaforementioned condition (1) is an important judging method of selectingan elongated metal plate.

Example 3

Similarly to the case of Example 1, 31^(st) to 37^(th) winding bodieswere manufactured, except that a target specification value of a platethickness of an elongated metal plate was 40 μm. In addition, similarlyto the case of Example 1, 31^(st) to 37^(th) masks were manufactured byusing the elongated metal plates of the 31^(st) to the 37^(th) windingbodies, except that a target specification value of a dimension of athrough-hole was 60 μm 60 μm. In addition, similarly to the case ofExample 1, a plate thickness of the elongated metal plates of the31^(st) to the 37^(th) winding bodies at the central portion in thewidth direction was measured along the longitudinal direction at manypoints. In addition, similarly to the case of Example 1, dimensions ofthe through-holes in the 31^(st) to the 37^(th) mask were measured. FIG.24(c) shows an average value A and a variation B in plate thickness inthe longitudinal direction of the elongated metal plates of the 31^(st)to the 37^(th) elongated metal plates. In addition, FIG. 25(c) shows avariation in dimension of the through-holes in the 31^(st) to the37^(th) masks.

As shown in FIG. 24(c), the 31^(st) to the 35^(th) winding bodiessatisfied the aforementioned condition (1). On the other hand, the36^(th) and the 37^(th) winding bodies did not satisfy theaforementioned condition (1). In addition, as shown in FIG. 25(c), inthe 31^(st) to the 35^(th) masks obtained from the elongated metalplates of the 31^(st) to the 35^(th) winding bodies, a variation indimension of the through-holes was restrained to 2.0 μm or less. On theother hand, in the 36^(th) and the 37^(th) masks obtained from theelongated metal plates of the 36^(th) and the 37^(th) elongated metalplates, a variation in dimension of the through-holes was over 2.0 μm.Namely, also when the target specification value of the plate thicknessof the elongated metal plate is 40 μm, it can be said that theaforementioned condition (1) is an important judging method of selectingan elongated metal plate.

Example 4

There was conducted a test to know a range in which the aforementionedcondition (1) is effective. The range means a deviation degree of anaverage plate thickness of an elongated metal plate in the longitudinaldirection D1 from a target specification value. To be specific, as shownin FIG. 26(a), there were prepared 41^(st) to 47^(th) winding bodieseach having an average plate thickness in the order of 20 μm as a targetspecification value. At this time, as shown in FIG. 26(a), there wereselected winding bodies whose variation in plate thickness of anelongated metal plate in the longitudinal direction D1 was close to anupper limit of the aforementioned condition (1), specifically, apercentage of a value obtained by dividing a variation B in platethickness by an average value of the plate thicknesses A(plate-thickness variation B/plate-thickness average value A×100(%)) wasabout 5%. FIG. 26(a) shows an average plate thickness A of the elongatedmetal plates of the 41^(st) to the 47^(th) winding bodies in thelongitudinal direction D1, a variation B in plate thickness of theelongated metal plates of the 41^(st) to the 47^(th) winding bodies inthe longitudinal direction D1, and (B/A)×100(%). In addition, FIG. 26(a)shows a value of {(A−20)/20}×100(%) which shows a deviation of theaverage plate thickness of an elongated metal plate in the longitudinaldirection D1 from the target specification value.

In addition, similarly to the case of Example 1, 41^(st) to 47^(th)masks were manufactured by using the elongated metal plates of the41^(st) to 47^(th) winding bodies. Further, dimensions of through-holesin the 41^(st) to the 47^(th) masks were measured. FIG. 27(a) shows avariation in dimension of the through-holes in the 41^(st) to the47^(th) masks. As described above with reference to FIG. 8A, when theplate thickness of an elongated metal plate is smaller than a targetspecification value, the portion 43 having a steep shape, i.e., the topportion 43 a possibly remains between the distal edges 32 of the wallsurfaces 31 of the first recesses 30 of the adjacent two through-holes25. FIG. 27(a) also shows a maximum value of a width of the top portion43 a, when such a top portion 43 a was observed. In order to manufacturean organic EL display device having a pixel density of 450 ppi or more,it is preferable that no top portion 43 a of the deposition mask 20exits, or otherwise it is preferable that the width of the top portion43 a is 2.0 μm or less.

As shown in FIG. 27(a), in the 42^(nd) to the 46^(th) masks, thevariation in dimension of the through-holes was restrained to 2.0 μm orless, and the width of the top portion was restrained to 2.0 μm or less.As shown in FIG. 26(a), in the 42^(nd) to the 46^(th) winding bodiesused for manufacturing the 42^(nd) to the 46^(th) masks, the deviationof the average plate thickness of the elongated metal plate in thelongitudinal direction D1 from the target specification value was withina range between −3%−+3%.

On the other hand, as shown in FIG. 27(a), in the 41^(st) mask, thewidth of the top portion was over 2.0 μm. In addition, in the 41^(st)winding body used for manufacturing the 41^(st) mask, the deviation ofthe average plate thickness of the elongated metal plate in thelongitudinal direction D1 from the target specification value was out ofthe range between −3%−+3%.

As shown in FIG. 27(a), in the 47^(th) mask, the variation in dimensionof the through-holes was over 2.0 μm. In the 47^(th) winding body usedfor manufacturing the 47^(th) mask, the deviation of the average platethickness of the elongated metal plate in the longitudinal direction D1from the target specification value was out of the range between−3%−+3%.

From these results, it can be said that, in order that theaforementioned condition (1) effectively functions, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value needs to be within therange between −3%−+3%.

Example 5

Similarly to the case of Example 4, 51^(st) to 57^(th) winding bodieswere prepared, except that a target specification value of a platethickness of an elongated metal plate was 25 μm. In addition, similarlyto the case of Example 4, 51^(st) to 57^(th) masks were manufactured byusing the elongated metal plates of the 51^(st) to the 57^(th) windingbodies, except that a target specification value of a dimension of athrough-hole was 40 μm×40 μm. In addition, similarly to the case ofExample 4, a plate thickness of the elongated metal plates of the51^(st) to the 57^(th) winding bodies at the central portion in thewidth direction was measured along the longitudinal direction at manypoints. In addition, similarly to the case of Example 4, the dimensionsof the through-holes in the 51^(st) to the 57^(th) masks and the widthsof the top portions thereof were measured. FIG. 26(b) shows an averagevalue A and a variation B in plate thickness in the longitudinaldirection of the elongated metal plates of the 51^(st) to the 57^(th)winding bodies. FIG. 26(b) also shows a value of {(A−25)/25}×100(%)which shows a deviation of the average plate thickness of the elongatedmetal plate in the longitudinal direction D1 from the targetspecification value. In addition, FIG. 27(b) shows a variation indimension of the through-holes in the 51^(st) to the 57^(th) masks, anda maximum dimension of the top portion.

As shown in FIG. 27(b), in the 52^(nd) to 55^(th) masks, the variationin dimension of the through-holes was restrained to 2.0 μm, and thewidth of the top portion was restrained to 2.0 μm. In addition, as shownin FIG. 26(b), in the 52^(nd) to 55^(th) winding bodies used formanufacturing the 52^(nd) to 55^(th) masks, the deviation of the averageplate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was within a rangebetween −3%−+3%.

On the other hand, as shown in FIG. 27(b), in the 51^(st) mask, thewidth of the top portion was over 2 μm. In addition, in the 51^(st)winding body used for manufacturing the 51^(st) mask, the deviation ofthe average plate thickness of the elongated metal plate in thelongitudinal direction D1 from the target specification value was out ofa range between −3%−+3%.

As shown in FIG. 27(b), in the 56^(th) and the 57^(th) mask, thevariation in dimension of the through-holes was over 2.0 μm. Inaddition, in the 56^(th) and the 57^(th) winding bodies used formanufacturing the 56^(th) and the 57^(th) masks, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was out of a rangebetween −3%−+3%.

From these results, also when the target specification value of theplate thickness of the elongated metal plate is 25 μm, in order that theaforementioned condition (1) effectively functions, it can be said thatthe deviation of the average plate thickness of the elongated metalplate in the longitudinal direction D1 from the target specificationvalue needs to be within a range between −3%−+3%.

Example 6

Similarly to the case of the above Example 4, 1^(st) to 67^(th) windingbodies were prepared, except that a target specification value of aplate thickness of an elongated metal plate was 40 μm. In addition,similarly to the case of the above Example 4, 61^(st) to 67^(th) maskswere manufactured by using the elongated metal plates of the 61^(st) tothe 67^(th) winding bodies, except that a target specification value ofa dimension of a through-hole was 60 μm×60 μm. In addition, similarly tothe case of Example 4, a plate thickness of the elongated metal platesof the 61^(st) to the 67th winding bodies at the central portion in thewidth direction were measured along the longitudinal direction at manypoints.

In addition, similarly to the case of Example 4, the dimensions of thethrough-holes in the 61^(st) to the 67^(th) masks and the widths of thetop portions thereof were measured. FIG. 26(c) shows an average value Aand a variation B in plate thickness in the longitudinal direction ofthe elongated metal plates of the 61^(st) to the 67^(th) winding bodies.FIG. 26(c) also shows a value of {(A−40)/40}×100(%) which shows adeviation of the average plate thickness of the elongated metal plate inthe longitudinal direction D1 from the target specification value. Inaddition, FIG. 27(c) shows a variation in dimension of the through-holesin the 61^(st) to the 67^(th) masks, and a maximum dimension of the topportion.

As shown in FIG. 27(c), in the 62^(nd) to the 65^(th) masks, thevariation in dimension of the through-holes was restrained to 2.0 μm,and the width of the top portion was restrained to 2.0 μm. As shown inFIG. 26(c), in the 62^(nd) to the 65^(th) winding bodies used formanufacturing the 62^(nd) to the 65^(th) masks, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was within a rangebetween −3%−+3%.

On the other hand, as shown in FIG. 27(c), in the 61^(st) mask, thewidth of the top portion was over 2.0 μm. In the 61^(st) winding bodyused for manufacturing the 61^(st) mask, the deviation of the averageplate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was out of a rangebetween −3%−+3%.

In addition, as shown in FIG. 27(c), in the 66^(th) and the 67^(th)masks, the deviation in dimension of the through-holes was over 2.0 μm.In addition, in the 66^(th) and the 67^(th) winding bodies used formanufacturing the 66^(th) and the 67^(th) masks, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was out of a rangebetween −3%−+3%.

From these results, also when the target specification value of theplate thickness of the elongated metal plate is 40 μm, in order that theaforementioned condition (1) effectively functions, it can be said thatthe deviation of the average plate thickness of the elongated metalplate in the longitudinal direction D1 from the target specificationvalue needs to be within a range between −3%−+3%.

Example 7

There was conducted a test for confirming that the aforementionedcondition (2) is effective. To be specific, as shown in FIG. 29(a),there were prepared 71^(st) to 79^(th) winding bodies each having anaverage thickness which deviated from 20 μm as a target specificationvalue by about 3%. At this time, as shown in FIG. 29(a), there wereselected winding bodies whose variation in thickness of an elongatedmetal plate in the longitudinal direction D1 was close to the upperlimit of the aforementioned condition (1), specifically, a percentage ofa value obtained by dividing the variation B in plate thickness by theaverage value of the plate thicknesses A (plate-thickness variation Bplate-thickness average value A×100(%)) was about 5%.

A plate thickness of the elongated metal plates of the 71^(st) to the79^(th) winding bodies was measured along the width direction at aplurality of points. To be specific, as shown in FIG. 28, the platethickness was measured at measurement points 102 the number of which was27, in a predetermined area near a first end portion 64 e in thelongitudinal direction D1 of the elongated metal plate 64. Thesemeasurement points 102 are located in a predetermined area that isdefined near the first end portion 64 e, for example, by a range of adistance S1 in the longitudinal direction D1 and by a range of adistance S2 in the width direction D2. Herein, the distance S1 and thedistance S2 were set to be 500 mm. The measurement points 102 weredetermined as intersections between nine imaginary lines extending onthe elongated metal plate 64 along the longitudinal direction D1 andthree imaginary lines extending on the elongated metal plate 64 alongthe width direction D2. In FIG. 28, a measurement point of the pluralityof measurement points 102, which is located at the central portion ofthe elongated metal plate 64 in the width direction D2, is shown by asymbol 103. The measurement point 103 is a point that is located at thecentral portion of the range of the distance S2 in the width directionD2. The measurement point 103 is also a point that is located at thecentral portion of the range of the distance S1 in the longitudinaldirection D1.

In this embodiment, as shown in FIG. 28, a plate thickness of theelongated metal plate 64 was measured not only at the twenty sevenmeasurement points 102 in the predetermined area near the first endportion 64 e, but also at the similar twenty seven measurement points102 in a predetermined area near a second end portion 64 f in thelongitudinal direction D1 of the elongated metal plate 64. Then, avariation in plate thickness in the predetermined area near the firstend portion 64 e (value obtained by multiplying a standard deviation by3), and a variation in plate thickness in the predetermined area nearthe second end portion 64 f (value obtained by multiplying a standarddeviation by 3) were respectively calculated. A greater one of thecalculated deviations in plate thickness is shown in FIG. 29(a) as“deviation C in plate thickness in width direction D2”. In addition,FIG. 29(a) shows, as “plate thickness X at central portion in the widthdirection D2”, a value of the plate thickness of the elongated metalplate 64 at the central measurement point 103 in the width direction D2,which was obtained when the plate thickness of the elongated metal plate64 was measured at the twenty seven measurement points 102 along thewidth direction D2, in order to calculate a standard deviation of theplate thicknesses of the elongated metal plate 64 in the width directionD2.

In addition, similarly to the case of Example 1, deposition masks(referred to as 71^(st) to 79^(th) masks herebelow) having a number ofthrough-holes formed therein were manufactured by using the elongatedmetal plates of the 71^(st) to the 79^(th) winding bodies. At this time,in order that a deviation in dimension of the through-holes in thedeposition mask, which is caused by a deviation in plate thickness ofthe elongated metal plate in the width direction, could be restrained asmuch as possible, positions of a plurality of nozzles for injectingetchant, which were arranged along the width direction of the elongatedmetal plate, were suitably adjusted. In addition, dimensions of thethrough-holes in the 71^(st) to the 79^(th) masks were measured. In thisexample, 10 sets of five masks assigned along the width direction weretaken out along the longitudinal direction from the elongated metalplate of a number of manufactured deposition masks, and dimensions ofthe through-holes were measured. Namely, the through-hole dimensionmeasurement was performed with the use of 50 masks for each of the71^(st) to the 79^(th) masks. As described above, since the number ofmeasurement points at which dimensions of the through-holes are measuredin one mask is 45, the number of N at which the dimensions of thethrough-holes in the respective 71^(st) to the 79^(th) masks aremeasured is 2250. FIG. 30(a) shows calculation results of a deviation indimension of the through-holes in the 71^(st) to 79^(th) masks.

As shown in FIG. 29(a), the 71^(st), the 72^(nd), the 74^(th), the 75th,the 77^(th) and the 78^(th) winding bodies satisfied the aforementionedcondition (2), Namely, a percentage of a value obtained by dividing thedeviation C in plate thickness in the width direction D2 by the platethickness X at the central portion of the width direction D2 was 3% orless. On the other hand, the 73^(rd), the 76^(th) and the 79^(th)winding bodies did not satisfy the aforementioned condition (2). Asshown in FIG. 30(a), in the 71^(st), the 72^(nd), the 74^(th), the75^(th), the 77^(th) and the 78^(th) mask obtained from the elongatedmetal plates of the 71^(st), the 72^(nd), the 74^(th), the 75^(th), the77^(th) and the 78^(th) winding bodies, the deviation in dimension ofthe through-holes was restrained to 2.0 μm or less. On the other hand,in the 73^(rd), the 76^(th) and the 79^(th) masks obtained from theelongated metal plates of the 73^(rd), the 76^(th) and the 79^(th)winding bodies, the deviation in dimension of the through-holes was over2.0 μm.

In this example, by using the elongated metal plate that satisfied theaforementioned condition (2), it was possible to manufacture adeposition mask having through-holes whose deviation in dimension of thethrough-holes in the width direction was within the allowable range.Namely, it can be considered that the aforementioned condition (2) is animportant judging method of selecting an elongated metal plate.

Example 8

Similarly to the case of above Example 7, 81^(st) to 89^(th) windingbodies were manufactured, except that a target specification value of aplate thickness of an elongated metal plate was 25 μm. In addition,similarly to the case of above Example 7, 81^(st) to 89^(th) masks weremanufactured by using the elongated metal plates of the 81^(st) to the89^(th) winding bodies, except that a target specification value of adimension of a through-hole was 40 μm×40 μm. In addition, similarly tothe case of Example 7, a plate thickness of the elongated metal platesof the 81^(st) to 89^(th) winding bodies was measured along the widthdirection at many points. In addition, similarly to the case of Example7, dimensions of the through-holes in the 81^(st) to the 89^(th) maskswere measured. FIG. 29(b) shows a deviation C in plate thickness of theelongated metal plates of the 81^(st) to the 89^(th) winding bodies inthe width direction, and a plate thickness X at the central portion inthe width direction, in addition to an average value A of the platethicknesses in the longitudinal direction and a deviation B. FIG. 30(b)shows a deviation in dimension of the through-holes in the 81^(st) tothe 89^(th) masks.

As shown in FIG. 29(b), the 81^(st), the 82^(nd), the 84^(th), the 85th,the 87^(th) and the 88^(th) winding bodies satisfied the aforementionedcondition (2). On the other hand, the 83^(rd), the 86th and the 89^(th)winding bodies did not satisfy the aforementioned condition (2). Asshown in FIG. 30(b), in the 81^(st), the 82^(nd), the 84^(th), the85^(th), the 87^(th) and the 88^(th) masks obtained from the elongatedmetal plates of the 81^(st), the 82^(nd), the 84^(th), the 85^(th), the87^(th) and the 88^(th) winding bodies, the deviation in dimension ofthe through-holes was restrained to 2.0 μm or less. On the other hand,in the 83^(rd), the 86^(th) and the 89^(th) masks obtained from theelongated metal plates of the 83^(rd), the 86^(th) and the 89^(th)winding bodies, the deviation in dimension of the through-holes was over2.0 μm. Thus, also when the target specification value of the platethickness of the elongated metal plate is 25 μm, it can be said that theaforementioned condition (2) is an important judging method of selectingan elongated metal plate.

Example 9

Similarly to the case of the above Example 7, 91^(st) to 99^(th) windingbodies were manufactured, except that a target specification value of aplate thickness of an elongated metal plate was 40 μm. In addition,similarly to the case of the above Example 7, 91^(st) to 99^(th) maskswere manufactured by using the elongated metal plates of the 91^(st) tothe 99^(th) winding bodies, except that a target specification value ofa dimension of a through-hole was 60×60 μm. In addition, similarly tothe case of Example 7, dimensions of through-holes in the 91^(st) to the99th masks were measured. FIG. 29(c) shows a deviation C in platethickness of the elongated metal plates of the 91^(st) to the 99^(th)winding bodies in the width direction and a plate thickness X at thecentral portion in the width direction, in addition to an average valueA and a deviation B in plate thickness in the longitudinal direction.FIG. 30(c) shows a deviation in dimension of the through-holes in the91^(st) to the 99^(th) masks.

As shown in FIG. 29(c), the 91^(st), the 92^(nd), the 94^(th), the95^(th), the 67^(th) and the 68^(th) winding bodies satisfied theaforementioned condition (2). On the other hand, the 93^(rd), the66^(th) and the 99^(th) winding bodies did not satisfy theaforementioned condition (2). As shown in FIG. 30(c), in the 91^(st),the 92^(nd), the 94^(th), the 95^(th), the 97^(th) and the 98^(th) masksobtained from the elongated metal plates of the 91^(st), the 92^(nd),the 94^(th), the 95^(th), the 97^(th) and the 98^(th) winding bodies,the deviation in dimension of the through-holes was restrained to 2.0 μmor less. On the other hand, in the 93^(rd), the 96^(th) and the 99^(th)masks obtained from the 93^(rd), the 96^(th) and the 99^(th) windingbodies, the deviation in plate thickness of the through-holes was over2.0 μm. Namely, also when the target specification value of the platethickness of the elongated metal plate is 40 μm, it can be said that theaforementioned condition (2) is an important judging method of selectingan elongated metal plate.

In the above Examples 1 to 9, the tests for confirming the efficienciesof the aforementioned conditions (1) and (2) were conducted to a metalplate manufactured by rolling a base metal. In the below Examples 11 to18, tests for confirming the efficiencies of the aforementionedconditions (1) and (2) were conducted to a metal plate manufactured byutilizing a plating process. Except a metal plate manufactured byutilizing a plating process, a target specification value of a platethickness of the metal plate and a dimension of a through-hole,measurement items and evaluation items in the below-described Examples10 to 18 are the same as those of the above-described Examples 1 to 9.In the below-described Examples 10 to 18, detailed description of thesame part as that of the above-described Examples 1 to 9 is suitablyomitted.

Example 10

Similarly to the case of Example 1, there was conducted a test forconfirming that the aforementioned condition (1) is effective. Firstly,an elongated metal plate made of an iron alloy containing nickel wasmanufactured by a plating process, by using, as a plating liquid, amixed solution of a solution containing nickel sulfamate and a solutioncontaining iron sulfamate. Then, there was performed the cutting step inwhich both ends of the elongated metal plate in the width direction werecut off over a predetermined range, whereby the width of the elongatedmetal plate was finally adjusted to a desired width, specifically, to awidth of 500 mm. Thereafter, the elongated metal plate was wound, and101^(st) to 107^(th) winding bodies were manufactured, similarly to thecase of the above Example 1. A target specification value of a platethickness of the elongated metal plate was 13 μm.

Then, similarly to the case of the above Example 1, a plate thickness ofthe elongated metal plate at the central portion in the width directionwas measured along the longitudinal direction at many points. FIG. 31(a)shows an average value A and a variation B in plate thickness in thelongitudinal direction of the plate thicknesses of the elongated mealplates of the 101^(st) to the 107^(th) winding bodies.

Similarly to the case of the above Example 1, 101^(st) to 107^(th) maskswere manufactured by using the elongated metal plates of the 101^(st) tothe 107^(th) winding bodies, except that a through-hole had a circularshape and that a target specification value of a dimension of thethrough-hole was 20 μm in diameter. FIG. 32(a) shows a deviation indimension of the through-holes in the 101^(st) to the 107^(th) masks.

As shown in FIG. 31(a), the 101^(st) to the 105^(th) winding bodiessatisfied the aforementioned condition (1). Namely, a percentage of avalue obtained by dividing the deviation A in plate thickness in thelongitudinal direction by the average value A of plate thicknesses inthe longitudinal direction was 5% or less. On the other hand, the106^(th) and the 107^(th) winding bodies did not satisfy theaforementioned condition (1). In addition, as shown in FIG. 32(a), inthe 101^(st) to the 105^(th) masks obtained from the elongated metalplates of the 101^(st) to the 105^(th) winding bodies, the deviation indimension of the through-holes was restrained to 1.5 μm or less. On theother hand, in the 106^(th) and the 107^(th) masks obtained from the106^(th) and the 107^(th) winding bodies, the deviation in dimension ofthe through-holes was over 1.5 μm. From these results, when a metalplate in which a target specification value of a plate thickness is 13μm is manufactured by utilizing a plating process, it is considered thatthe aforementioned condition (1) is an important judging method ofselecting an elongated metal plate. In order to manufacture an organicEL display device having a pixel density of 800 ppi or more, it ispreferable that a deviation in dimension of through-holes in thedeposition mask 20 is 1.5 μm or less.

Example 11

Similarly to the case of the above Example 10, 111^(th) to 117^(th)winding bodies were manufactured, except that a target specificationvalue of a plate thickness of an elongated metal plate was 20 μm. Inaddition, 111^(th) to 117^(th) masks were manufactured by using theelongated metal plates of the 111^(th) and the 117^(th) winding bodies,except that a target specification value of a dimension of athrough-hole was 30 μm in diameter. In addition, similarly to the caseof Example 10, a plate thickness of the elongated metal plates of the111^(th) and the 117^(th) winding bodies at the central portion in thewidth direction was measured along the longitudinal direction at manypoints. Similarly to the case of Example 10, dimensions of through-holesin the 111^(th) to the 117^(th) masks were measured. FIG. 31(b) shows anaverage value A and a deviation B in plate thickness of the longitudinaldirection of the elongated metal plates of the 111^(th) and the 117^(th)winding bodies. FIG. 32(b) shows a deviation in dimension of thethrough-holes in the 111^(th) and the 117^(th) mask.

As shown in FIG. 31(b), the 111^(th) and the 115^(th) winding bodiessatisfied the aforementioned condition (1). On the other hand, the116^(th) and the 117^(th) winding bodies did not satisfy theaforementioned condition (1). As shown in FIG. 32(b), in the 111^(th)and the 115^(th) masks obtained from the elongated metal plates of the111^(th) and the 115^(th) winding bodies, the deviation in dimension ofthe through-holes was restrained to 2.0 μm. On the other hand, in the116^(th) and the 117^(th) mask obtained from the elongated metal platesof the 116^(th) and the 117^(th) winding bodies, the deviation indimension of the through-holes was over 2.0 μm. Namely, also when anelongated metal plate in which a target specification value of a platethickness is 20 μm, it can be said that the aforementioned condition (1)is an important judging method for selecting an elongated metal plate.

Example 12

Similarly to the case of the above Example 10, 121^(st) to 127^(th)winding bodies were manufactured, except that a target specificationvalue of a plate thickness of an elongated metal plate was 25 μm. Inaddition, similarly to the case of the above Example 10, 121^(st) to127^(th) masks were manufactured by using the elongated metal plates ofthe 121^(st) to the 127^(th) winding bodies, except that a targetspecification value of a dimension of a through-hole was 40 μm indiameter. Similarly to the case of Example 10, a plate thickness of theelongated metal plates of the 121^(st) to the 127^(th) winding bodies atthe central portion in the width direction was measured along thelongitudinal direction at many points. Similarly to the case of Example10, dimensions of through-holes in the 121^(st) to the 127^(th) maskswere measured. FIG. 31(c) shows an average value A and a deviation B inplate thickness in the longitudinal direction of the elongated metalplates of the 121^(st) to the 127^(th) winding bodies. FIG. 32(c) showsa deviation in dimension of the through-holes in the 121^(st) to the127^(th) masks.

As shown in FIG. 31(c), the 121^(st) to the 125^(th) winding bodiessatisfied the aforementioned condition (1). On the other hand, the126^(th) and the 127^(th) winding bodies did not satisfy theaforementioned condition (1). As shown in FIG. 32(c), in the 121^(st) tothe 125^(th) masks obtained from the elongated metal plates of the121^(st) to the 125^(th), the deviation in dimension of thethrough-holes was restrained to 2.0 μm or less. On the other hand, inthe 126^(th) and the 127^(th) masks obtained from the elongated metalplates of the 126^(th) and the 127^(th) winding bodies, the deviation indimension of the through-holes was over 2.0 μm. Namely, also when anelongated metal plate in which a target specification value of a platethickness is 25 μm, it can be said that the aforementioned condition (1)is an important judging method for selecting an elongated metal plate.

Example 13

Similarly to the case of the above Example 4, there was conducted a testto a metal plate manufactured by a plating process, to know a range inwhich the aforementioned condition (1) is effective. The range means adeviation degree of an average plate thickness of an elongated metalplate in the longitudinal direction D1 from a target specificationvalue. To be specific, as shown in FIG. 33(a), similarly to the case ofExample 10, there were prepared 131^(st) to 137^(th) winding bodies eachhaving an average thickness in the order of 13 μm as a targetspecification value. The 131^(st) to the 137^(th) winding bodies weremanufactured by a plating process. FIG. 33(a) shows an average platethickness A of an elongated metal plate in the longitudinal directionD1, a variation B in plate thickness of an elongated metal plate in thelongitudinal direction D1, and (B/A)×100(%). FIG. 33(a) also shows avalue of {(A−13)/13}×100(%) which shows a deviation of the average platethickness of an elongated metal plate in the longitudinal direction D1from the target specification value.

Similarly to the case of the above Example 4, 131^(st) to 137^(th) maskswere manufactured by using the elongated metal plates of the 131^(st) tothe 137^(th) winding bodies, except that a through-hole had a circularshape and that a target specification value of a dimension of thethrough-hole was 20 μm in diameter. Further, similarly to the case ofExample 4, dimensions of through-holes in the 131^(st) to the 137^(th)masks were measured. Similarly to the case of Example 4, FIG. 34(a) alsoshows a maximum value of a width of the top portion 43 a, when such atop portion 43 a was observed.

As shown in FIG. 34(a), in the 133^(rd) to the 135^(th) masks, thedeviation in dimension of the through-holes was restrained to 1.5 μm orless, and the width of the top portion was restrained to 2.0 μm or less.In addition, as shown in FIG. 33(a), in the 133^(rd) to the 135^(th)winding bodies used for manufacturing the 133^(rd) to the 135^(th)masks, the deviation of the average plate thickness of the elongatedmetal plate in the longitudinal direction D1 from the targetspecification value was within a range between −3%−+3%.

On the other hand, as shown in FIG. 34(a), in the 131^(st) and the132^(nd) masks, the width of the top portion was over 2.0 μm. Inaddition, in the 131^(st) and the 132^(nd) winding bodies used formanufacturing the 131^(st) and the 132^(nd) masks, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was out of the rangebetween −3%−+3%.

As shown in FIG. 34(a), in the 136^(th) and the 137^(th) masks, thedeviation in dimension of through-holes was over 1.5 μm. In addition, inthe 136^(th) and the 137^(th) winding bodies used for manufacturing the136^(th) and the 137^(th) masks, the deviation of the average platethickness of the elongated metal plate in the longitudinal direction D1from the target specification value was out of the range between−3%−+3%.

From these results, also when an elongated metal plate in which a targetspecification value of a plate thickness is 13 μm is manufactured byutilizing a plating process, it can be said that, in order that theaforementioned condition (1) effectively functions, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value needs to be within therange between −3%−+3%.

Example 14

Similarly to the case of the above Example 13, 141^(st) to 147^(th)winding bodies were prepared, except that a target specification valueof a plate thickness of an elongated metal plate was 20 μm. In addition,similarly to the case of the above Example 13, 141^(st) to 147^(th)masks were manufactured by using the elongated metal plates of the141^(st) to the 147^(th) winding bodies, except that a targetspecification value of a dimension of a through-hole was 30 μm indiameter. Similarly to the case of Example 13, a plate thickness of theelongated metal plates of the 141^(st) to the 147^(th) winding bodies atthe central portion in the width direction was measured along thelongitudinal direction at many points. Similarly to the case of Example13, a dimension of a through-hole and a width of a top portion of the141^(st) to the 147^(th) masks were measured. FIG. 33(b) shows anaverage value A and a deviation B in plate thickness in the longitudinaldirection of the elongated metal plates of the 141^(st) to the 147^(th)winding bodies. FIG. 33(b) also shows a value of {(A−20)/20}×100(%)which shows a deviation of the average plate thickness of an elongatedmetal plate in the longitudinal direction D1 from the targetspecification value. FIG. 34(b) shows a deviation in dimension ofthrough-holes in the 141^(st) to the 147^(th) masks, and a maximumdimension of a top portion thereof.

As shown in FIG. 34(b), in the 142^(nd) to the 146^(th) masks, thedeviation in dimension of the through-holes was restrained to 2.0 μm orless, and the width of the top portion was restrained to 2.0 μm or less.In addition, as shown in FIG. 33(b), in the 142^(nd) to the 146^(th)winding bodies used for manufacturing the 142^(nd) to the 146^(th)masks, the deviation of the average plate thickness of the elongatedmetal plate in the longitudinal direction D1 from the targetspecification value was within a range between −3%−+3%.

On the other hand, as shown in FIG. 34(b), in the 141^(st) mask, thewidth of the top portion was over 2.0 μm. In addition, in the 141^(st)winding body used for manufacturing the 141^(st) mask, the deviation ofthe average plate thickness of the elongated metal plate in thelongitudinal direction D1 from the target specification value was out ofthe range between −3%−+3%.

As shown in FIG. 34(b), in the 147^(th) mask, the deviation in dimensionof through-holes was over 2.0 μm. In addition, in the 147^(th) windingbody used for manufacturing the 147^(th) mask, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was out of the rangebetween −3%−+3%.

From these results, also when an elongated metal plate in which a targetspecification value of a plate thickness is 20 μm is manufactured byutilizing a plating process, it can be said that, in order that theaforementioned condition (1) effectively functions, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value needs to be within therange between −3%−+3%.

Example 15

Similarly to the case of the above Example 13, 151^(st) to 157^(th)winding bodies were prepared, except that a target specification valueof a plate thickness of an elongated metal plate was 25 μm. In addition,similarly to the case of the above Example 13, 151^(st) to 157^(th)masks were manufactured by using the elongated metal plates of the151^(st) to the 157^(th) winding bodies, except that a targetspecification value of a dimension of a through-hole was 40 μm indiameter. Similarly to the case of Example 13, a plate thickness of theelongated metal plates of the 151^(st) to the 157^(th) winding bodies atthe central portion in the width direction was measured along thelongitudinal direction at many points. Similarly to the case of Example13, a dimension of a through-hole and a width of a top portion of the151^(st) to the 157^(th) masks were measured. FIG. 33(c) shows anaverage value A and a deviation B in plate thickness in the longitudinaldirection of the elongated metal plates of the 151^(st) to the 157^(th)winding bodies. FIG. 33(c) also shows a value of {(A−25)/25}×100(%)which shows a deviation of the average plate thickness of an elongatedmetal plate in the longitudinal direction D1 from the targetspecification value. In addition, FIG. 34(c) shows a deviation indimension of through-holes in the 151^(st) to the 157^(th) masks, and amaximum dimension of a top portion thereof thereof.

As shown in FIG. 34(c), in the 153^(rd) to the 156^(th) masks, thedeviation in dimension of the through-holes was restrained to 2.0 μm orless, and the width of the top portion was restrained to 2.0 μm or less.In addition, as shown in FIG. 33(c), in the 153^(rd) to the 156^(th)winding bodies used for manufacturing the 153^(rd) to the 156^(th)masks, the deviation of the average plate thickness of the elongatedmetal plate in the longitudinal direction D1 from the targetspecification value was within a range between −3%−+3%.

On the other hand, as, shown in FIG. 34(c), in the 151^(st) and the152^(nd) masks, the width of the top portion was over 2.0 trn. In the151^(st) and the 152^(nd) winding bodies used for manufacturing the151^(st) and the 152^(nd) masks, the deviation of the average platethickness of the elongated metal plate in the longitudinal direction D1from the target specification value was out of the range between−3%−+3%.

As shown in FIG. 34(c), in the 157^(th) mask, the deviation in dimensionof through-holes was over 2 μm. In addition, in the 157^(th) windingbody used for manufacturing the 157^(th) mask, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value was out of the rangebetween −3%−+3%.

From these results, also when an elongated metal plate in which a targetspecification value of a plate thickness is 25 m is manufactured byutilizing a plating process, it can be said that, in order that theaforementioned condition (1) effectively functions, the deviation of theaverage plate thickness of the elongated metal plate in the longitudinaldirection D1 from the target specification value needs to be within therange between −3%−+3%.

Example 16

Similarly to the case of the above Example 7, there was conducted a testfor confirming that the aforementioned condition (2) is effective, to ametal plate manufactured by a plating process. To be specific, as shownin FIG. 35(a), similarly to the case of Example 10, there were prepared161^(st) to 169^(th) winding bodies each having an average platethickness which deviated, from 13 μm as a target specification value byabout 3%. The 161^(st) to the 169^(th) winding bodies were manufacturedby a plating process,

Similarly to the case of the above Example 7, a plate thickness of theelongated metal plates of the 161^(st) to the 169^(th) winding bodieswas measured along the width direction at a plurality of points. FIG.35(a) shows a “deviation C in plate thickness in width direction D2” anda “plate thickness X at central portion in width direction D2”.

In addition, similarly to the case of Example 10, deposition masks(referred to as 161^(st) to the 169^(th) masks herebelow) having anumber of circular through-holes formed therein were manufactured byusing the elongated metal plates of the 161^(st) to the 169^(th) windingbodies, such that a target specification value of a through-hole was 20μm in diameter. At this time, similarly to the case of the above example7, in order that a deviation in dimension of the through-holes in thedeposition mask, which is caused by a deviation in plate thickness ofthe elongated metal plate in the width direction, could be restrained asmuch as possible, positions of a plurality of nozzles for injectingetchant, which were arranged along the width direction of the elongatedmetal plate, were suitably adjusted. In addition, similarly to the caseof the above Example 7, dimensions of the through-holes in the 161^(st)to the 169^(th) masks were measured. FIG. 36(a) shows calculationresults of a deviation in dimension of the through-holes in the 161^(st)to the 169^(th) masks.

As shown in FIG. 35(a), the 161^(st), the 162^(nd), the 164^(th), the165^(th), 167^(th) and the 168^(th) winding bodies satisfied theaforementioned condition (2). Namely, a percentage of a value obtainedby dividing the deviation C in plate thickness in the width direction D2by the plate thickness X at the central portion of the width directionD2 was 3% or less. On the other hand, the 163^(rd), the 166^(th) and the169^(th) winding bodies did not satisfy the aforementioned condition(2). As shown in FIG. 36(a), in the 161^(st), the 162^(nd), the164^(th), the 165^(th), 167^(th) and the 168^(th) masks obtained fromthe elongated metal plates of the 161^(st), the 162^(nd), the 164^(th),the 165^(th), 167^(th) and the 168^(th) winding bodies, the deviation indimension of the through-holes was restrained to 1.5 μm or less. On theother hand, in the 163^(rd), the 166^(th) and the 169^(th) masksobtained from the 163^(rd) the 166^(th) and the 169^(th) winding bodies,the deviation in dimension of the through-holes was over 1.5 μm.

In this example, by using an elongated metal plate satisfying theaforementioned condition (2), it was possible to manufacture adeposition mask having through-holes whose deviation in dimension of thethrough-holes in the width direction was within an allowable range.Namely, also when an elongated metal plate in which a targetspecification value is 13 μm is manufactured by utilizing a platingprocess, it is considered that the aforementioned condition (2) is animportant judging method of selecting an elongated metal plate.

Example 17

Similarly to the case of the above Example 16, 171^(st) to 179^(th)winding bodies were manufactured, except that a target specificationvalue of a plate thickness of an elongated metal plate was 20 μm. Inaddition, similarly to the case of the above Example 16, 171^(st) to179^(th) masks were manufactured by using the elongated metal plates ofthe 171^(st) to the 179^(th) winding bodies were manufactured, exceptthat a target specification value of a dimension of a through-hole was30 μm in diameter. Similarly to the case of Example 16, a platethickness of the elongated metal plates of the 171^(st) to the 179^(th)winding bodies was measured along the width direction at many points. Inaddition, similarly to the case of Example 16, dimension ofthrough-holes in the 171^(st) to the 179^(th) masks were measured. FIG.35(b) shows a variation C in plate thickness in the width direction ofthe elongated metal plates of the 171^(st) to the 179^(th) windingbodies and a plate thickness X at the central portion in the widthdirection thereof, in addition to an average value A and a deviation Bin plate thickness in the longitudinal direction. FIG. 36(b) shows adeviation in dimension of the through-holes in the 171^(st) to the179^(th) masks.

As shown in FIG. 35(b), the 171^(st) the 172^(nd), the 174^(th), the175^(th), 177^(th) and the 178^(th) winding bodies satisfied theaforementioned condition (2). On the other hand, the 173^(rd), 176^(th)and 179^(th) winding bodies did not satisfy the aforementioned condition(2). As shown in FIG. 36(b), in the 171^(st), the 172^(nd), the174^(th), the 175^(th), 177^(th) and the 178^(th) masks obtained fromthe elongated metal, plates of the 171^(st), the 172^(nd), the 174^(th),the 175^(th), 177^(th) and the 178^(th) winding bodies, the deviation indimension of the through-holes was restrained to 2.0 μm or less. On theother hand, in the 173^(rd), 176^(th) and 179^(th) masks obtained fromthe elongated metal plates of the 173^(rd), 176^(th) and 179^(th)winding bodies, the deviation in dimension of the through-holes was over2.0 μm. Namely, also when an elongated metal plate in which a targetspecification value of a plate thickness is 20 μm, it can be said thatthe aforementioned condition (2) is an important judging method forselecting an elongated metal plate.

Example 18

Similarly to the case of the above Example 16, 181^(st) to 189^(th)winding bodies were manufactured, except that a target specificationvalue of a plate thickness of an elongated metal plate was 25 μm. Inaddition, similarly to the case of the above Example 16, 181^(st) to189^(th) masks were manufactured by using the elongated metal plates ofthe 181^(st) to 189^(th) winding bodies, except that a targetspecification value of a dimension of a through-hole was 40 μm indiameter. Similarly to the case of Example 16, a plate thickness of theelongated metal plates of the 181^(st) to 189^(th) winding bodies wasmeasured along the width direction at many points. In addition,similarly to the case of Example 7, dimensions of through-holes in the181^(st) to 189^(th) masks were measured. FIG. 35(c) shows a variation Cin plate thickness in width direction of the elongated metal plates ofthe 181^(st) to 189^(th) winding bodies and a plate thickness X at thecentral portion in the width direction thereof, in addition to anaverage value A and a variation B in plate thickness in the longitudinaldirection.

As shown in FIG. 35(c), the 181^(st), the 182^(nd), the 184^(th), the185^(th), the 187^(th) and the 188^(th) winding bodies satisfied theaforementioned condition (2). On the other hand, the 183^(rd), the186^(th) and the 189^(th) winding bodies did not satisfy theaforementioned condition (2). As shown in FIG. 36(c), in the 181^(st),the 182^(nd), the 184^(th), the 185^(th), the 187^(th) and the 188^(th)masks obtained from elongated metal plates of the 181^(st), the182^(nd), the 184th, the 185^(th), the 187^(th) and the 188^(th), thedeviation in dimension of the through-holes was restrained to 2.0 μm orless. On the other hand, in the 183^(rd), the 186^(th) and the 189^(th)mask obtained from the elongated metal plates of the 183^(rd), the 186thand the 189^(th) winding bodies, the deviation in dimension of thethrough-holes was over 2.0 μm. Namely, also when an elongated metalplate in which a target specification value of a plate thickness is 25μm, it can be said that the aforementioned condition (2) is an importantjudging method for selecting an elongated metal plate.

-   20 Deposition mask-   21 Metal plate-   21 a First surface of metal plate-   21 b Second surface of metal plate-   22 Effective area-   23 Peripheral area-   25 Through-hole-   30 First recess-   31 Wall surface-   32 Distal edge of wall surface-   35 Second recess-   36 Wall surface-   43 a Top portion-   55 Base metal-   56 Rolling apparatus-   57 Annealing apparatus-   61 Core-   62 Winding body-   64 Elongated metal plate-   65 a, 65 b Resist pattern-   65 c, 65 d Resist film

1. A method of manufacturing an elongated metal plate used formanufacturing a deposition mask having a plurality of through-holesformed in the metal plate, the method comprising: a rolling step ofrolling a base metal to obtain the metal plate having an average valueof plate thicknesses in a longitudinal direction within a ±3% rangearound a predetermined value; and a cutting step of cutting off one endand the other end of the metal plate in a width direction over apredetermined range; wherein the following two conditions (1) and (2)are satisfied as to a variation in plate thickness of the metal plate:(1) when an average value of the plate thicknesses of the metal plate inthe longitudinal direction is represented as A, and a value obtained bymultiplying a standard deviation of the plate thicknesses of the metalplate in the longitudinal direction by 3 is represented as B,(B/A)×100(%) is 5% or less; and (2) when a value obtained by multiplyinga standard deviation of the plate thicknesses of the metal plate in thewidth direction by 3 is represented as C, and a value of a platethickness of the metal plate at a central portion in the widthdirection, which is obtained when plate thicknesses of the metal plateare measured along the width direction in order to calculate thestandard deviation of the plate thicknesses of the metal plate in thewidth direction, is represented as X, (C/X)×100(%) is 3% or less.
 2. Amethod of manufacturing an elongated metal plate used for manufacturinga deposition mask having a plurality of through-holes formed in themetal plate, the method comprising: a film forming step of obtaining themetal plate by a plating process, wherein an average value of platethicknesses of the metal plate in a longitudinal direction is within a±3% range around a predetermined value; and a cutting step of cuttingoff one end and the other end of the metal plate in a width directionover a predetermined range; wherein the following two conditions (1) and(2) are satisfied as to a variation in plate thickness of the metalplate: (1) when an average value of the plate thicknesses of the metalplate in the longitudinal direction is represented as A, and a valueobtained by multiplying a standard deviation of the plate thicknesses ofthe metal plate in the longitudinal direction by 3 is represented as B,(B/A)×100(%) is 5% or less; and (2) when a value obtained by multiplyinga standard deviation of the plate thicknesses of the metal plate in thewidth direction by 3 is represented as C, and a value of a platethickness of the metal plate at a central portion in the widthdirection, which is obtained when plate thicknesses of the metal plateare measured along the width direction in order to calculate thestandard deviation of the plate thicknesses of the metal plate in thewidth direction, is represented as X, (C/X)×100(%) is 3% or less.
 3. Themethod of manufacturing the metal plate according to claim 1, whereinthe plate thickness of the metal plate is 80 μm or less.
 4. The methodof manufacturing a metal plate according to claim 1, wherein: thestandard deviation of the plate thicknesses in the width direction ofthe metal plate is calculated based on the plate thicknesses of themetal plate, the plate thicknesses being measured at intersectionsbetween m imaginary lines (m is a natural number of 2 or more) extendingon the metal plate in the longitudinal direction and n imaginary line(s)(n is a natural number of 1 or more) extending on the elongated metalplate in the width direction; and m>n.
 5. The method of manufacturing ametal plate according to claim 1, wherein the base metal is made of aniron alloy containing nickel.
 6. An elongated metal plate used formanufacturing a deposition mask having a plurality of through-holesformed in the metal plate, wherein: an average value of platethicknesses in a longitudinal direction of the metal plate is within a±3% range around a predetermined value; and the following two conditions(1) and (2) are satisfied as to a variation in plate thickness of themetal plate: (1) when an average value of the plate thicknesses of themetal plate in the longitudinal direction is represented as A, and avalue obtained by multiplying a standard deviation of the platethicknesses of the metal plate in the longitudinal direction by 3 isrepresented as B, (B/A)×100(%) is 5% or less; and (2) when a valueobtained by multiplying a standard deviation of the plate thicknesses ofthe metal plate in the width direction by 3 is represented as C, and avalue of the plate thickness of the metal plate in a central portion inthe width direction, which is obtained when the plate thickness of themetal plate is measured along the width direction in order to calculatethe standard deviation of the plate thicknesses of the metal plates inthe width direction is represented as C, (C/X)×100(%) is 3% or less. 7.The metal plate according to claim 6, wherein the plate thickness of themetal plate is 80 μm or less.
 8. The metal plate according to claim 6,wherein the standard deviation of the plate thicknesses in the widthdirection of the metal plate is calculated based on the platethicknesses of the metal plate, the plate thicknesses being measured atintersections between m imaginary lines (m is a natural number of 2 ormore) extending on the metal plate in the longitudinal direction and nimaginary line(s) (n is a natural number of 1 or more) extending on theelongated metal plate in the width direction; and m>n.
 9. The metalplate according to claim 6, wherein the base metal is made of an ironalloy containing nickel.
 10. A method of manufacturing a deposition maskhaving a plurality of through-holes formed therein, the methodcomprising: a step of preparing an elongated metal plate having anaverage value of plate thicknesses in a longitudinal direction is withina ±3% range around a predetermined value; a resist-pattern forming stepof forming a resist pattern on the metal plate; and an etching step ofetching an area of the metal plate, which is not covered with the resistpattern, to form a recess which becomes a through-hole in the metalplate; wherein the following two conditions (1) and (2) are satisfied asto a variation in plate thickness of the metal plate: (1) when anaverage value of the plate thicknesses of the metal plate in thelongitudinal direction is represented as A, and a value obtained bymultiplying a standard deviation of the plate thicknesses of the metalplate in the longitudinal direction by 3 is represented as B,(B/A)×100(%) is 5% or less; and (2) when a value obtained by multiplyinga standard deviation of the plate thicknesses of the metal plate in thewidth direction by 3 is represented as C, and a value of a platethickness of the metal plate at a central portion in the widthdirection, which is obtained when plate thicknesses of the metal plateare measured along the width direction in order to calculate thestandard deviation of the plate thicknesses of the metal plate in thewidth direction, is represented as X, (C/X)×100(%) is 3% or less. 11.The method of manufacturing a deposition mask according to claim 10,wherein the plate thickness of the metal plate is 80 μm or less.
 12. Themethod of manufacturing a deposition mask according to claim 10, whereinthe standard deviation of the plate thicknesses in the width directionof the metal plate is calculated based on the plate thicknesses of themetal plate, the plate thicknesses being measured at intersectionsbetween m imaginary lines (m is a natural number of 2 or more) extendingon the metal plate in the longitudinal direction and n imaginary line(s)(n is a natural number of 1 or more) extending on the elongated metalplate in the width direction; and m>n.
 13. The method of manufacturing adeposition mask according to claim 10, wherein the base metal is made ofan iron alloy containing nickel.
 14. The method of manufacturing adeposition mask according to claim 10, wherein: the deposition mask hasa first surface and a second surface, the first surface facing adeposition material and the second surface facing a substrate when thedeposition material is deposited onto the substrate using the depositionmask; the resist pattern formed by the resist-pattern forming stepincludes a first resist pattern formed on a first surface of the metalplate, which corresponds to the first surface of the deposition mask,and a second resist pattern formed on a second surface of the metalplate, which corresponds to the second surface of the deposition mask;the recess formed by the etching step includes a plurality of firstrecesses formed by etching an area of the first surface of the metalplate, which is not covered with the first resist pattern, and aplurality of second recesses formed by etching an area of the secondsurface of the metal plate, which is not covered with the second resistpattern; the etching step is performed such that the first recess andthe second recess corresponding to the first recess are connected toeach other; and a distance from the second surface of the depositionmask to a connection portion where the first recess and the secondrecess are connected, in a direction along a normal direction of themetal plate is 6 μm or less.
 15. The method of manufacturing adeposition mask according to claim 14, wherein: the deposition maskincludes an effective area in which the plurality of through-holes areformed, and a peripheral area located around the effective area; and theetching step is performed such that the first surface of the metal plateis etched over all the effective area.
 16. The method of manufacturing adeposition mask according to claim 14, wherein: the deposition maskincludes an effective area in which the plurality of through-holes areformed, and a peripheral area located around the effective area; and theetching step is performed such that the first surface of the metal plateis not etched over all the effective area, so that a portion that is notetched remains as a top portion.